qcacmn: Remove dp_tx_pdev_detach API

dp_tx_pdev_detach API takes care of flushing
tx descriptors and multicast enhancement mem
cleanup

dp_pdev_deinit takes care of cleaning up the
above actions and dp_tx_pdev_detach is simply
a redundant piece of code

Hence remove dp_tx_pdev_detach API and call
dp_tx_desc_flush directly from dp_pdev_deinit

CRs-Fixed: 2769303
Change-Id: Ic798793e81eefc7dc905ca7552fdca13e9fddd8c

dp/wifi3.0/dp_main.c

@@ -4276,7 +4276,7 @@ static void dp_pdev_deinit(struct cdp_pdev *txrx_pdev, int force)
 		qdf_nbuf_free(pdev->sojourn_buf);
 
 	dp_pdev_flush_pending_vdevs(pdev);
-	dp_tx_pdev_detach(pdev);
+	dp_tx_desc_flush(pdev, NULL, true);
 	dp_pktlogmod_exit(pdev);
 	dp_neighbour_peers_detach(pdev);