s390: require mvcos facility, not tod clock steering facility

Inlined uaccess functions require the mvcos facility (bit 27), not the tod
clock steering facility (bit 28) for z10 and newer machines.

Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>