s390: clean up redundant facilities list setup

Facilities list in the lowcore is initially set up by verify_facilities
from als.c and later initializations are redundant, so cleaning them up.

Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>