qcacmn: Send frame as multicast if snoop entry not found

Send control packets as mcast even though snoop entry is not found
instead of dropping the frame. These control frames include IGMP/MLD
frames that is required to add the snoop entry.

Change-Id: If905b54e2ae9eaa3943428b36b1b894bcd528785
CRs-Fixed: 2133270

dp/wifi3.0/dp_tx.c

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2016-2017 The Linux Foundation. All rights reserved.
+ * Copyright (c) 2016-2018 The Linux Foundation. All rights reserved.
  *
  * Permission to use, copy, modify, and/or distribute this software for
  * any purpose with or without fee is hereby granted, provided that the
@@ -1744,11 +1744,10 @@ qdf_nbuf_t dp_tx_send(void *vap_dev, qdf_nbuf_t nbuf)
 			DP_STATS_INC_PKT(vdev,
 					tx_i.mcast_en.mcast_pkt, 1,
 					qdf_nbuf_len(nbuf));
-			if (dp_tx_prepare_send_me(vdev, nbuf)) {
+			if (dp_tx_prepare_send_me(vdev, nbuf) > 0) {
 				qdf_nbuf_free(nbuf);
 				return NULL;
 			}
-			return nbuf;
 		}
 	}
 #endif