x66, UV: Enable 64-bit ACPI MFCG support for SGI UV2 platform

Enable 64-bit ACPI MFCG support for SGI UV2 platform. The check
is similar to the check on UV1. UV2 has a different oem_id
string.

Signed-off-by: Jack Steiner <steiner@sgi.com>
Link: http://lkml.kernel.org/r/20110602195943.GA27079@sgi.com


Signed-off-by: Ingo Molnar <mingo@elte.hu>