We got several false bug reports because of enabled
CONFIG_DETECT_SOFTLOCKUP.  Disable soft lockup detection on s390, since it
doesn't work on a virtualized architecture.

Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>