rsi: Send rx filter frame to device when interface is down

When interface is down it is better to stop all RX packets to
host. 0xffff will block all packets to host.
Signed-off-by: Prameela Rani Garnepudi <prameela.j04cs@gmail.com>
Signed-off-by: Amitkumar Karwar <amit.karwar@redpinesignals.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

drivers/net/wireless/rsi/rsi_91x_mac80211.c

@@ -301,6 +301,10 @@ static void rsi_mac80211_stop(struct ieee80211_hw *hw)
 
 	mutex_lock(&common->mutex);
 	common->iface_down = true;
+
+	/* Block all rx frames */
+	rsi_send_rx_filter_frame(common, 0xffff);
+
 	mutex_unlock(&common->mutex);
 }