NSM: Remove !nsm check from nsm_release()

The nsm_release() function should never be called with a NULL handle
point.  If it is, that's a bug.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>

fs/lockd/mon.c

@@ -288,8 +288,6 @@ found:
  */
 void nsm_release(struct nsm_handle *nsm)
 {
-	if (!nsm)
-		return;
 	if (atomic_dec_and_lock(&nsm->sm_count, &nsm_lock)) {
 		list_del(&nsm->sm_link);
 		spin_unlock(&nsm_lock);