wlcore: ignore dummy packet events in PLT mode

Sometimes the firmware sends a dummy packet event while we are in PLT
mode.  This doesn't make sense, it's a firmware bug.  Fix this by
ignoring dummy packet events when we're PLT mode.
Reported-by: NYegor Yefremov <yegorslists@googlemail.com>
Reported-by: NArik Nemtsov <arik@wizery.com>
Signed-off-by: NLuciano Coelho <luca@coelho.fi>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

drivers/net/wireless/ti/wlcore/event.c

@@ -158,6 +158,11 @@ EXPORT_SYMBOL_GPL(wlcore_event_channel_switch);
 
 void wlcore_event_dummy_packet(struct wl1271 *wl)
 {
+	if (wl->plt) {
+		wl1271_info("Got DUMMY_PACKET event in PLT mode.  FW bug, ignoring.");
+		return;
+	}
+
 	wl1271_debug(DEBUG_EVENT, "DUMMY_PACKET_ID_EVENT_ID");
 	wl1271_tx_dummy_packet(wl);
 }