x86/platform/uv: Fix UV4 hub revision adjustment

Currently, UV4 is incorrectly identified as UV4A and UV4A as UV5. Hub
chip starts with revision 1, fix it.

 [ bp: Massage commit message. ]

Fixes: 647128f1 ("x86/platform/uv: Update UV MMRs for UV5")
Signed-off-by: Mike Travis <mike.travis@hpe.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Steve Wahl <steve.wahl@hpe.com>
Acked-by: Dimitri Sivanich <dimitri.sivanich@hpe.com>
Link: https://lkml.kernel.org/r/20201203152252.371199-1-mike.travis@hpe.com