This patch introduces a notifier chain for cpu idle.  There are two events
CPU_IDLE and CPU_NOT_IDLE that are called just before the cpu goes to sleep
and right after the cpu woke up again.  The notifier is used to simplify the
no-hz-timer-in-idle feature and the virtual cpu timers.  In addition the
virtual cpu timer functions have been moved to arch/s390/kernel/vtime.c, which
gives a nice separation between the timer functions related to real time and
the timer functions related to virtual cpu time.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>