udf: Explain handling of load_nls() failure

Add comment explaining that load_nls() failure gets handled back in
udf_fill_super() to avoid false impression that it is unhandled.
Signed-off-by: NJan Kara <jack@suse.cz>

fs/udf/super.c

@@ -572,6 +572,11 @@ static int udf_parse_options(char *options, struct udf_options *uopt,
 			if (!remount) {
 				if (uopt->nls_map)
 					unload_nls(uopt->nls_map);
+				/*
+				 * load_nls() failure is handled later in
+				 * udf_fill_super() after all options are
+				 * parsed.
+				 */
 				uopt->nls_map = load_nls(args[0].from);
 				uopt->flags |= (1 << UDF_FLAG_NLS_MAP);
 			}