[PATCH] add cpu_relax to hrtimer_cancel

Add a cpu_relax() to the hand-coded spinwait in hrtimer_cancel().

Signed-off-by: Joe Korty <joe.korty@ccur.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>