ath9k: Register larger listen interval

Notify the AP that we may be sleeping longer to allow the AP power
save code to buffer larger number of frames for us when using virtual
wiphys.

Signed-off-by: Jouni Malinen <jouni.malinen@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/ath9k/main.c b/drivers/net/wireless/ath9k/main.c
index 183fb8e..7c20da3 100644
--- a/drivers/net/wireless/ath9k/main.c
+++ b/drivers/net/wireless/ath9k/main.c
@@ -1597,6 +1597,7 @@
 	hw->queues = 4;
 	hw->max_rates = 4;
 	hw->channel_change_time = 5000;
+	hw->max_listen_interval = 10;
 	hw->max_rate_tries = ATH_11N_TXMAXTRY;
 	hw->sta_data_size = sizeof(struct ath_node);
 	hw->vif_data_size = sizeof(struct ath_vif);