multifd: remove used parameter from send_recv_pages() method

It is already there as p->pages->num.

Signed-off-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
diff --git a/migration/multifd.h b/migration/multifd.h
index 7968cc5..e57adc7 100644
--- a/migration/multifd.h
+++ b/migration/multifd.h
@@ -167,7 +167,7 @@
     /* Cleanup for receiving side */
     void (*recv_cleanup)(MultiFDRecvParams *p);
     /* Read all pages */
-    int (*recv_pages)(MultiFDRecvParams *p, uint32_t used, Error **errp);
+    int (*recv_pages)(MultiFDRecvParams *p, Error **errp);
 } MultiFDMethods;
 
 void multifd_register_ops(int method, MultiFDMethods *ops);