x86, uv: More Westmere support on SGI UV

Enable Westmere support for all APIC modes on SGI UV.

Signed-off-by: Russ Anderson <rja@sgi.com>
LKML-Reference: <20101028224132.GB15804@sgi.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>