libnvdimm: Use PAGE_SIZE instead of SZ_4K for align check

Architectures have different page size than 4K. Use the PAGE_SIZE
to make sure ranges are correctly aligned.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Link: https://lore.kernel.org/r/20190905154603.10349-7-aneesh.kumar@linux.ibm.com


Signed-off-by: Dan Williams <dan.j.williams@intel.com>