nfit: fix region registration vs block-data-window ranges

Commit 1cf03c00 "nfit: scrub and register regions in a workqueue"
mistakenly attempts to register a region per BLK aperture. There is
nothing to register for individual apertures as they belong as a set to
a BLK aperture group that are registered with a corresponding
DIMM-control-region. Filter them for registration to prevent some
needless devm_kzalloc() allocations.

Cc: <stable@vger.kernel.org>
Fixes: 1cf03c00 ("nfit: scrub and register regions in a workqueue")
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>