ath9k: Handle full sleep in ps_restore.

IDLE PS (Full Sleep) doesn't work when ifconfig up
is done during Idle unassociated state.
Fix this by restoring FULL SLEEP in ps_restore if CONF_IDLE
is set.

Signed-off-by: Vivek Natarajan <vnatarajan@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/ath/ath9k/ath9k.h b/drivers/net/wireless/ath/ath9k/ath9k.h
index bdbcc70..3f8a7e7 100644
--- a/drivers/net/wireless/ath/ath9k/ath9k.h
+++ b/drivers/net/wireless/ath/ath9k/ath9k.h
@@ -480,6 +480,7 @@
 	u8 nbcnvifs;
 	u16 nvifs;
 	bool ps_enabled;
+	bool ps_idle;
 	unsigned long ps_usecount;
 	enum ath9k_int imask;