s390: exclude early C code from gcov profiling

Early C code must be excluded from gcov profiling since it may write
to the bss section before
- a potential initrd that resides there is rescued
- the bss section is initialized (zeroed)

This patch only addresses the problem that early code is instrumented
for profiling, but not the problem that it jumps into other code that
is still instrumented. That problem will be fixed with a follow-on
patch.
Reviewed-by: NPeter Oberparleiter <oberpar@linux.vnet.ibm.com>
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

arch/s390/kernel/Makefile

@@ -46,6 +46,7 @@ CFLAGS_als.o		+= -march=z900
 AFLAGS_REMOVE_head.o	+= $(CC_FLAGS_MARCH)
 AFLAGS_head.o		+= -march=z900
 endif
+GCOV_PROFILE_early.o := n
 GCOV_PROFILE_sclp.o := n
 GCOV_PROFILE_als.o := n
 UBSAN_SANITIZE_als.o := n