fix(risc-v/virt64, cpp): add spaces to fix Wliteral-suffix

[Tang-Haojin]

拉取/合并请求描述：(PR description)

[

为什么提交这份PR (why to submit this PR)

在编译 bsp/qemu-virt64-riscv 时，我尝试打开了 cpp 支持：

diff --git a/bsp/qemu-virt64-riscv/.config b/bsp/qemu-virt64-riscv/.config
index 3a1a2558f1..9db5bc73fa 100644
--- a/bsp/qemu-virt64-riscv/.config
+++ b/bsp/qemu-virt64-riscv/.config
@@ -392,7 +392,7 @@ CONFIG_RT_USING_POSIX_PIPE_SIZE=512
 # end of Interprocess Communication (IPC)
 # end of POSIX (Portable Operating System Interface) layer
 
-# CONFIG_RT_USING_CPLUSPLUS is not set
+CONFIG_RT_USING_CPLUSPLUS=y
 # end of C/C++ and POSIX layer
 
 #

在这一操作过后，编译时遇到了 (1) 一个error 和 (2) 一个warning。这个 PR 是为了解决问题 (2)，问题 (1) 的 PR 已在 #10651 分别提出。

问题现象

开启 CONFIG_RT_USING_CPLUSPLUS 后，编译报 Wliteral-suffix：

In file included from /nfs/home/tanghaojin/rt-thread-3/libcpu/risc-v/common64/cpuport.h:15,
                 from /nfs/home/tanghaojin/rt-thread-3/include/rthw.h:26,
                 from /nfs/home/tanghaojin/rt-thread-3/include/rtatomic.h:14,
                 from /nfs/home/tanghaojin/rt-thread-3/include/rtthread.h:35,
                 from /nfs/home/tanghaojin/rt-thread-3/components/libc/cplusplus/cxx_crt.cpp:11:
/nfs/home/tanghaojin/rt-thread-3/libcpu/risc-v/virt64/opcode.h:32:5: warning: invalid suffix on literal; C++11 requires a space between literal and string macro [-Wliteral-suffix]
   32 |     ".insn r "RT_STRINGIFY(opcode)","RT_STRINGIFY(func3)","RT_STRINGIFY(func7)","RT_STRINGIFY(rd)","RT_STRINGIFY(rs1)","RT_STRINGIFY(rs2)
      |     ^
/nfs/home/tanghaojin/rt-thread-3/libcpu/risc-v/virt64/opcode.h:32:35: warning: invalid suffix on literal; C++11 requires a space between literal and string macro [-Wliteral-suffix]
   32 |     ".insn r "RT_STRINGIFY(opcode)","RT_STRINGIFY(func3)","RT_STRINGIFY(func7)","RT_STRINGIFY(rd)","RT_STRINGIFY(rs1)","RT_STRINGIFY(rs2)
      |                                   ^
/nfs/home/tanghaojin/rt-thread-3/libcpu/risc-v/virt64/opcode.h:32:57: warning: invalid suffix on literal; C++11 requires a space between literal and string macro [-Wliteral-suffix]
   32 |     ".insn r "RT_STRINGIFY(opcode)","RT_STRINGIFY(func3)","RT_STRINGIFY(func7)","RT_STRINGIFY(rd)","RT_STRINGIFY(rs1)","RT_STRINGIFY(rs2)
      |                                                         ^
/nfs/home/tanghaojin/rt-thread-3/libcpu/risc-v/virt64/opcode.h:32:79: warning: invalid suffix on literal; C++11 requires a space between literal and string macro [-Wliteral-suffix]
   32 |     ".insn r "RT_STRINGIFY(opcode)","RT_STRINGIFY(func3)","RT_STRINGIFY(func7)","RT_STRINGIFY(rd)","RT_STRINGIFY(rs1)","RT_STRINGIFY(rs2)
      |                                                                               ^
/nfs/home/tanghaojin/rt-thread-3/libcpu/risc-v/virt64/opcode.h:32:98: warning: invalid suffix on literal; C++11 requires a space between literal and string macro [-Wliteral-suffix]
   32 |     ".insn r "RT_STRINGIFY(opcode)","RT_STRINGIFY(func3)","RT_STRINGIFY(func7)","RT_STRINGIFY(rd)","RT_STRINGIFY(rs1)","RT_STRINGIFY(rs2)
      |                                                                                                  ^
/nfs/home/tanghaojin/rt-thread-3/libcpu/risc-v/virt64/opcode.h:32:118: warning: invalid suffix on literal; C++11 requires a space between literal and string macro [-Wliteral-suffix]
   32 |     ".insn r "RT_STRINGIFY(opcode)","RT_STRINGIFY(func3)","RT_STRINGIFY(func7)","RT_STRINGIFY(rd)","RT_STRINGIFY(rs1)","RT_STRINGIFY(rs2)
      |

你的解决方案是什么 (what is your solution)

按照 warning 信息，为字符串常量和宏之间添加空格。

请提供验证的bsp和config (provide the config and bsp)

• BSP: bsp/qemu-virt64-riscv

• .config: CONFIG_RT_USING_CPLUSPLUS=y

• action:

]

当前拉取/合并请求的状态 Intent for your PR

必须选择一项 Choose one (Mandatory):

• 本拉取/合并请求是一个草稿版本 This PR is for a code-review and is intended to get feedback
• 本拉取/合并请求是一个成熟版本 This PR is mature, and ready to be integrated into the repo

代码质量 Code Quality：

我在这个拉取/合并请求中已经考虑了 As part of this pull request, I've considered the following:

• 已经仔细查看过代码改动的对比 Already check the difference between PR and old code
• 代码风格正确，包括缩进空格，命名及其他风格 Style guide is adhered to, including spacing, naming and other styles
• 没有垃圾代码，代码尽量精简，不包含#if 0代码，不包含已经被注释了的代码 All redundant code is removed and cleaned up
• 所有变更均有原因及合理的，并且不会影响到其他软件组件代码或BSP All modifications are justified and not affect other components or BSP
• 对难懂代码均提供对应的注释 I've commented appropriately where code is tricky
• 代码是高质量的 Code in this PR is of high quality
• 已经使用formatting 等源码格式化工具确保格式符合RT-Thread代码规范 This PR complies with RT-Thread code specification
• 如果是新增bsp, 已经添加ci检查到.github/ALL_BSP_COMPILE.json 详细请参考链接BSP自查

[github-actions]

📌 Code Review Assignment

🏷️ Tag: libcpu_riscv

Reviewers: @Yaochenger

Changed Files (Click to expand)

• libcpu/risc-v/virt64/opcode.h

---

📊 Current Review Status (Last Updated: 2025-09-01 14:11 CST)

• ⌛ @Yaochenger Pending Review

---

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