qcacmn: disable EXT grp irqs and drain TXRX during suspend

Any update to the SRNG TP/HP when the device is in low power
state would result in system errors. It is recommended to disable
EXT grp irqs and drain TXRX before sending power save enter command
to the FW. This will ensure that no interrupts are received while
in power save mode and as a result there wont be any HP/TP updates.

Change-Id: Ibf952bbc2c6d13fb3e4ca6b4845bc9cc887fa694
CRs-Fixed: 2883135

dp/inc/cdp_txrx_ops.h

@@ -566,6 +566,7 @@ struct cdp_cmn_ops {
 					  ol_txrx_rx_fp rx,
 					  ol_osif_peer_handle osif_peer);
 #endif /* QCA_SUPPORT_WDS_EXTENDED */
+	void (*txrx_drain)(ol_txrx_soc_handle soc);
 };
 
 struct cdp_ctrl_ops {