lockd: fix sparse warning in svcshare.c

fs/lockd/svcshare.c:74:50: warning: Using plain integer as NULL pointer
Signed-off-by: NHarvey Harrison <harvey.harrison@gmail.com>
Cc: Neil Brown <neilb@suse.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

fs/lockd/svcshare.c

@@ -71,7 +71,8 @@ nlmsvc_unshare_file(struct nlm_host *host, struct nlm_file *file,
 	struct nlm_share	*share, **shpp;
 	struct xdr_netobj	*oh = &argp->lock.oh;
 
-	for (shpp = &file->f_shares; (share = *shpp) != 0; shpp = &share->s_next) {
+	for (shpp = &file->f_shares; (share = *shpp) != NULL;
+					shpp = &share->s_next) {
 		if (share->s_host == host && nlm_cmp_owner(share, oh)) {
 			*shpp = share->s_next;
 			kfree(share);