dvb: Flag unused callback parameter.

modules/access/dvb/http.c

@@ -253,6 +253,7 @@ static int HttpCallback( httpd_file_sys_t *p_args,
                          uint8_t *_psz_request,
                          uint8_t **_pp_data, int *pi_data )
 {
+    VLC_UNUSED(p_file);
     access_sys_t *p_sys = p_args->p_access->p_sys;
     char *psz_request = (char *)_psz_request;
     char **pp_data = (char **)_pp_data;