Fix this allnoconfig build breakage:

arch/s390/boot/mem_detect.c: In function 'tprot':
arch/s390/boot/mem_detect.c:122:12: error: 'EFAULT' undeclared (first use in this function)
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>