fix the following sparse warning:

 kernel/hrtimer.c:665:34: warning: incorrect type in argument 2 (different address spaces)
 kernel/hrtimer.c:665:34:    expected void const *from
 kernel/hrtimer.c:665:34:    got struct timespec [noderef] *<noident><asn:1>
 kernel/hrtimer.c:664:2: warning: dereference of noderef expression
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>