x86, UV: Add support for SGI UV2 hub chip

x86, UV: Add support for SGI UV2 hub chip

This patch adds support for a new version of the SGI UV hub
chip. The hub chip is the node controller that connects multiple
blades into a larger coherent SSI.

For the most part, UV2 is compatible with UV1. The majority of
the changes are in the addresses of MMRs and in a few cases, the
contents of MMRs. These changes are the result in changes in the
system topology such as node configuration, processor types,
maximum nodes, physical address sizes, etc.

Signed-off-by: Jack Steiner <steiner@sgi.com>
Link: http://lkml.kernel.org/r/20110511175028.GA18006@sgi.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>