audit_alloc_mark(): don't open-code ERR_CAST()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

kernel/audit_fsnotify.c

@@ -84,7 +84,7 @@ struct audit_fsnotify_mark *audit_alloc_mark(struct audit_krule *krule, char *pa
 
 	dentry = kern_path_locked(pathname, &path);
 	if (IS_ERR(dentry))
-		return (void *)dentry; /* returning an error */
+		return ERR_CAST(dentry); /* returning an error */
 	inode = path.dentry->d_inode;
 	inode_unlock(inode);