s390/sclp: disable FORTIFY_SOURCE for early sclp code

Michal Suchánek reported the following compile error with
FORTIFY_SOURCE enabled:

drivers/s390/char/sclp_early_core.o: In function `memcpy':
include/linux/string.h:340: undefined reference to `fortify_panic'

To fix this simply disable FORTIFY_SOURCE on the early sclp code as
well, which I forgot on the initial commit.

Fixes: 79962038dffa ("s390: add support for FORTIFY_SOURCE")
Reported-by: Michal Suchánek <msuchanek@suse.de>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

drivers/s390/char/Makefile

@@ -17,6 +17,8 @@ CFLAGS_REMOVE_sclp_early_core.o	+= $(CC_FLAGS_MARCH)
 CFLAGS_sclp_early_core.o		+= -march=z900
 endif
 
+CFLAGS_sclp_early_core.o		+= -D__NO_FORTIFY
+
 obj-y += ctrlchar.o keyboard.o defkeymap.o sclp.o sclp_rw.o sclp_quiesce.o \
 	 sclp_cmd.o sclp_config.o sclp_cpi_sys.o sclp_ocf.o sclp_ctl.o \
 	 sclp_early.o sclp_early_core.o