retain the bf16 capability in fallback versions of the -march option for NeoverseN2

Makefile.arm64

@@ -145,13 +145,13 @@ ifeq (1, $(filter 1,$(GCCMINORVERSIONGTEQ4) $(GCCVERSIONGTEQ11) $(ISCLANG)))
 ifneq ($(OSNAME), Darwin)
 CCOMMON_OPT += -march=armv8.5-a+sve+sve2+bf16 -mtune=neoverse-n2
 else
-CCOMMON_OPT += -march=armv8.2-a+sve -mtune=cortex-a72
+CCOMMON_OPT += -march=armv8.2-a+sve+bf16 -mtune=cortex-a72
 endif
 ifneq ($(F_COMPILER), NAG)
 FCOMMON_OPT += -march=armv8.5-a+sve+sve2+bf16 -mtune=neoverse-n2
 endif
 else
-CCOMMON_OPT += -march=armv8.5-a+sve
+CCOMMON_OPT += -march=armv8.5-a+sve+bf16
 ifneq ($(CROSS), 1)
 CCOMMON_OPT += -mtune=native
 endif
@@ -163,13 +163,13 @@ endif
 endif
 endif
 else
-CCOMMON_OPT += -march=armv8.2-a+sve -mtune=cortex-a72
+CCOMMON_OPT += -march=armv8.2-a+sve+bf16 -mtune=cortex-a72
 ifneq ($(F_COMPILER), NAG)
 FCOMMON_OPT += -march=armv8.2-a -mtune=cortex-a72
 endif
 endif
 else
-CCOMMON_OPT += -march=armv8-a+sve -mtune=cortex-a72
+CCOMMON_OPT += -march=armv8-a+sve+bf16 -mtune=cortex-a72
 ifneq ($(F_COMPILER), NAG)
 FCOMMON_OPT += -march=armv8-a -mtune=cortex-a72
 endif