M467: Support CAN bus

1.  Update BSP CANFD driver
2.  Notes for implementation
    (1) Each CANFD instance supports two IRQ lines. Use only line 0. Line 1 is not used.
    (2) For Rx disabling multiple filter handles,
        1)  Map all filter handles to filter handle 0
        2)  Use Rx FIFO 0 for filter handle 0
    (3) For Rx enabling multiple filter handles,
        1)  Use Rx FIFO 0 for filter handle 0
        2)  Use Rx FIFO 1 for filter handle through first invoking can_filter()
        3)  Use dedicated Rx Buffer for other filter handles
        NOTE: H/W supports mask on Rx FIFO 0/1 but not on dedicated Rx Buffer.
    (4) For Tx, use only dedicated Tx Buffer. BSP CANFD driver doesn't support Tx FIFO/Queue.
    (5) Support no CAN FD.

Author: ccli8

targets/TARGET_NUVOTON/TARGET_M460/CMakeLists.txt

@@ -13,6 +13,7 @@ target_sources(mbed-m460
     INTERFACE
         analogin_api.c
         analogout_api.c
+        can_api.c
 
         crypto/crypto-misc.cpp
 

targets/TARGET_NUVOTON/TARGET_M460/README.md

@@ -1,5 +1,14 @@
 # Nuvoton M460 series
 
+## CAN
+
+Current CAN HAL implementation has the following characteristics:
+
+1.  By default, filter handle 0 is configured to accept all messages as requested.
+1.  Support only single filter handle semantics, that is, filter handle 0.
+    The `handle` argument passed to `can_filter()` or `can_read()` is ignored.
+    All filter related operations are done on filter handle 0.
+
 ## HyperRAM
 
 HyperRAM, via Hyper Bus Interface Controller (HBI), is mapped to two regions: `0x0A00_0000`–`0x0BFF_FFFF` and `0x8000_0000`–`0x81FF_FFFF`, through which CPU can direct access.