x86, uv: Ensure hub revision set for all ACPI modes.

Ensure that UV hub revision is set for all ACPI modes.

Signed-off-by: Russ Anderson <rja@sgi.com>
LKML-Reference: <20100115180908.GB7757@sgi.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>