x86/platform/uv: Update UV[23] platform code for SNC

Previous Sub-NUMA Clustering changes need not just a count of blades
present, but a count that includes any missing ids for blades not
present; in other words, the range from lowest to highest blade id.

Signed-off-by: Steve Wahl <steve.wahl@hpe.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Link: https://lore.kernel.org/all/20230519190752.3297140-9-steve.wahl%40hpe.com