Revert "Disable make_armc6 on v8m"

This reverts commit a2427998f9.

tools/export/makefile/__init__.py

@@ -265,17 +265,6 @@ class Armc6(Arm):
     NAME = 'Make-ARMc6'
     TOOLCHAIN = "ARMC6"
 
-    @classmethod
-    def is_target_supported(cls, target_name):
-        target = TARGET_MAP[target_name]
-        if target.core in (
-                "Cortex-M23", "Cortex-M23-NS",
-                "Cortex-M33", "Cortex-M33-NS"
-        ):
-            return False
-        return apply_supported_whitelist(
-            cls.TOOLCHAIN, cls.POST_BINARY_WHITELIST, target)
-
 
 class IAR(Makefile):
     """IAR specific makefile target"""