x86, UV: Clean up UV headers for MMR definitions

Update UV mmr definitions header file. Eliminate definitions no
longer needed. Move 2 definitions from tlb_uv.c into the header
file where they belong.

Signed-off-by: Jack Steiner <steiner@sgi.com>
LKML-Reference: <20100310204458.GA28835@sgi.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>