refs: mark unused parameters in do_for_each_reflog_helper()

This is an each_ref_fn callback, so it has to match that interface. We
marked most of these in 63e14ee (refs: mark unused each_ref_fn
parameters, 2022-08-19), but in this case:

  - this function was created in 31f8983 (refs: drop unused params
    from the reflog iterator callback, 2024-02-21), and most of the
    arguments were correctly mark as UNUSED, but "flags" was missed.

  - commit e820771 (refs: add referent to each_ref_fn, 2024-08-09)
    added a new argument to the each_ref_fn callback. In most callbacks
    it added an UNUSED annotation, but it missed one case.

Signed-off-by: Jeff King <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: peff

refs.c

@@ -2390,9 +2390,10 @@ struct do_for_each_reflog_help {
 	void *cb_data;
 };
 
-static int do_for_each_reflog_helper(const char *refname, const char *referent,
+static int do_for_each_reflog_helper(const char *refname,
+				     const char *referent UNUSED,
 				     const struct object_id *oid UNUSED,
-				     int flags,
+				     int flags UNUSED,
 				     void *cb_data)
 {
 	struct do_for_each_reflog_help *hp = cb_data;