arm64: vdso: Don't use gcc plugins for building vgettimeofday.c

Don't use gcc plugins for building arch/arm64/kernel/vdso/vgettimeofday.c
to avoid unneeded instrumentation.
Signed-off-by: Alexander Popov <alex.popov@linux.com>
Link: https://lore.kernel.org/r/20200624123330.83226-4-alex.popov@linux.comSigned-off-by: Will Deacon <will@kernel.org>

arch/arm64/kernel/vdso/Makefile

@@ -30,7 +30,7 @@ ldflags-y := -shared -nostdlib -soname=linux-vdso.so.1 --hash-style=sysv	\
 ccflags-y := -fno-common -fno-builtin -fno-stack-protector -ffixed-x18
 ccflags-y += -DDISABLE_BRANCH_PROFILING
 
-CFLAGS_REMOVE_vgettimeofday.o = $(CC_FLAGS_FTRACE) -Os $(CC_FLAGS_SCS)
+CFLAGS_REMOVE_vgettimeofday.o = $(CC_FLAGS_FTRACE) -Os $(CC_FLAGS_SCS) $(GCC_PLUGINS_CFLAGS)
 KBUILD_CFLAGS			+= $(DISABLE_LTO)
 KASAN_SANITIZE			:= n
 UBSAN_SANITIZE			:= n