Use ARMC5 for FVP targets

Author: SenRamakri

targets/targets.json

@@ -7694,7 +7694,7 @@
     "FVP_MPS2": {
         "inherits": ["ARM_FM"],
         "public": false,
-        "supported_toolchains": ["GCC_ARM", "ARM", "IAR"],
+        "supported_toolchains": ["GCC_ARM", "ARMC5", "IAR"],
         "OUTPUT_EXT": "elf",
         "device_has": [
             "AACI",