notes: mark unused callback parameters

for_each_note() requires a callback, but not all callbacks need all of
the parameters. Likewise, init_notes() takes a callback to implement the
"combine" strategy, but the "ignore" variant obviously doesn't look at
its arguments at all. Mark unused parameters as appropriate to silence
compiler warnings.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/notes.c

@@ -113,8 +113,9 @@ static void free_note_data(struct note_data *d)
 }
 
 static int list_each_note(const struct object_id *object_oid,
-		const struct object_id *note_oid, char *note_path,
-		void *cb_data)
+			  const struct object_id *note_oid,
+			  char *note_path UNUSED,
+			  void *cb_data UNUSED)
 {
 	printf("%s %s\n", oid_to_hex(note_oid), oid_to_hex(object_oid));
 	return 0;