ath9k_htc: Handle WMI timeouts properly

If a WMI command has timed out for some reason,
a late WMI response would end up updating the
response region of a new WMI request that has been
issued in the meantime.

Fix this race condition by dropping a WMI response
if a new WMI command has been issued.

Signed-off-by: Sujith <Sujith.Manoharan@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/ath/ath9k/wmi.h b/drivers/net/wireless/ath/ath9k/wmi.h
index fd8c9c5f..6113571 100644
--- a/drivers/net/wireless/ath/ath9k/wmi.h
+++ b/drivers/net/wireless/ath/ath9k/wmi.h
@@ -97,6 +97,7 @@
 	enum htc_endpoint_id ctrl_epid;
 	struct mutex op_mutex;
 	struct completion cmd_wait;
+	enum wmi_cmd_id last_cmd_id;
 	u16 tx_seq_id;
 	u8 *cmd_rsp_buf;
 	u32 cmd_rsp_len;