fix(ggml): correct RISC-V ISA string canonical ordering for RVV in CMake (ggml-org#20888)

Signed-off-by: ihb2032 <hebome@foxmail.com>

Author: ihb2032

ggml/src/ggml-cpu/CMakeLists.txt

@@ -460,27 +460,32 @@ function(ggml_add_cpu_backend_variant_impl tag_name)
         endif()
         if(NOT GGML_CPU_ALL_VARIANTS)
             set(MARCH_STR "rv64gc")
+            if (GGML_RVV)
+                string(APPEND MARCH_STR "v")
+            endif()
+
             if (GGML_RV_ZFH)
                 string(APPEND MARCH_STR "_zfh")
             endif()
 
             if (GGML_XTHEADVECTOR)
                 string(APPEND MARCH_STR "_xtheadvector")
             elseif (GGML_RVV)
-                string(APPEND MARCH_STR "_v")
                 if (GGML_RV_ZVFH)
                     string(APPEND MARCH_STR "_zvfh")
                 endif()
                 if (GGML_RV_ZVFBFWMA)
                     string(APPEND MARCH_STR "_zvfbfwma")
                 endif()
             endif()
+
             if (GGML_RV_ZICBOP)
                 string(APPEND MARCH_STR "_zicbop")
             endif()
             if (GGML_RV_ZIHINTPAUSE)
                 string(APPEND MARCH_STR "_zihintpause")
             endif()
+
             list(APPEND ARCH_FLAGS "-march=${MARCH_STR}" -mabi=lp64d)
         else()
             # Begin with the lowest baseline