Fixes clang: error: unknown argument: '-mno-thumb-interwork' for armv7

--- a/arch/arm/Makefile
+++ b/arch/arm/Makefile
@@ -104,9 +104,9 @@
 tune-y := $(tune-y)
 
 ifeq ($(CONFIG_AEABI),y)
-CFLAGS_ABI	:=-mabi=aapcs-linux -mno-thumb-interwork -mfpu=vfp
+CFLAGS_ABI	:=-mabi=aapcs-linux -mfpu=vfp
 else
-CFLAGS_ABI	:=$(call cc-option,-mapcs-32,-mabi=apcs-gnu) $(call cc-option,-mno-thumb-interwork,)
+CFLAGS_ABI	:=$(call cc-option,-mapcs-32,-mabi=apcs-gnu)
 endif
 
 ifeq ($(CONFIG_ARM_UNWIND),y)