[PATCH] x86_64: Always use IO-APIC routing for timer.

I tested it on a couple of chipsets and it worked everywhere so it
should be ok as default for now.

So far I haven't done the great purge of the useless old check_timer
code yet though.

Can be overwritten with enable_8254_timer in the worst case

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>