pmem, dax: have direct_access use __pmem annotation

pmem, dax: have direct_access use __pmem annotation

Orabug: 22913653

Update the annotation for the kaddr pointer returned by direct_access()
so that it is a __pmem pointer.  This is consistent with the PMEM driver
and with how this direct_access() pointer is used in the DAX code.

Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
(cherry picked from commit e2e05394e4a3420dab96f728df4531893494e15d)
Signed-off-by: Dan Duval <dan.duval@oracle.com>