x86/platform/uv/BAU: Add uv_bau_version enumerated constants

Define enumerated constants for each UV hub version and replace magic
numbers with the appropriate constant.

Signed-off-by: Andrew Banman <abanman@hpe.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Cc: sivanich@hpe.com
Cc: rja@hpe.com
Cc: mike.travis@hpe.com
Cc: akpm@linux-foundation.org
Link: http://lkml.kernel.org/r/1489077734-111753-2-git-send-email-abanman@hpe.com


Signed-off-by: Thomas Gleixner <tglx@linutronix.de>