[PATCH] hrtimers: simplify nanosleep

nanosleep is the only user of the expired state, so let it manage this itself,
which makes the hrtimer code a bit simpler.  The remaining time is also only
calculated if requested.

Signed-off-by: Roman Zippel <zippel@linux-m68k.org>
Acked-by: Ingo Molnar <mingo@elte.hu>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>