x86/platform/UV: Fix GAM Range Table entries less than 1GB

The latest UV platforms include the new ApachePass NVDIMMs into the
UV address space.  This has introduced address ranges in the Global
Address Map Table that are less than the previous lowest range, which
was 2GB.  Fix the address calculation so it accommodates address ranges
from bytes to exabytes.

Signed-off-by: Mike Travis <mike.travis@hpe.com>
Reviewed-by: Andrew Banman <andrew.banman@hpe.com>
Reviewed-by: Dimitri Sivanich <dimitri.sivanich@hpe.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Russ Anderson <russ.anderson@hpe.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20180205221503.190219903@stormcage.americas.sgi.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>