It does not return an error, so we don't need to check the return value
for IS_ERR().  Indeed, it is a bug to do so; with a sufficiently large
PFN, a legitimate DAX entry may be mistaken for an error return.
Signed-off-by: NMatthew Wilcox <mawilcox@microsoft.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>