x86/platform/UV: Add Support for UV4 Hubless NMIs

Merge new UV Hubless NMI support into existing UV NMI handler.

Signed-off-by: Mike Travis <travis@sgi.com>
Reviewed-by: Russ Anderson <rja@hpe.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Dimitri Sivanich <sivanich@hpe.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20170125163517.585269837@asylum.americas.sgi.com


Signed-off-by: Ingo Molnar <mingo@kernel.org>