x86, mce: unify, prepare for 32-bit v2

Prepare the 64-bit mce_64.c code side to be built on 32-bit.

[ includes ifdef relocation by Andi Kleen ]

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Cc: Andi Kleen <ak@firstfloor.org>
Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>