The IO APIC code had lots of duplicated code to read/write 64bit
routing entries into the IO-APIC. Factor this out int common read/write
functions

In a few cases the IO APIC lock is taken more often now, but this
isn't a problem because it's all initialization/shutdown only
slow path code.

Similar to earlier x86-64 patch.

Includes a fix by Jiri Slaby for a mistake that broke resume
Signed-off-by: Andi Kleen <ak@suse.de>