qcacmn: enable MEC support for Beryllium

The multicast echo check feature is moved to hardware in
Beryllium. Enable this hardware feature and also disable
the MEC handing code for Beryllium in the host.

Change-Id: I86d319963191f3ed77aba16dcccbc659906edd9f

dp/wifi3.0/dp_tx.c

@@ -4381,6 +4381,7 @@ void dp_tx_process_htt_completion(struct dp_soc *soc,
 	 * descriptor in case of MEC notify.
 	 */
 	if (tx_status == HTT_TX_FW2WBM_TX_STATUS_MEC_NOTIFY) {
+		qdf_assert_always(!soc->mec_fw_offload);
 		/*
 		 * Get vdev id from HTT status word in case of MEC
 		 * notification