iwlwifi: use scan while idle

As idle is just a deep powersave mode for
the device, it will easily scan while idle
since that turns off powersave.

This reduces the number of commands sent
to the device when scanning.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/iwlwifi/iwl-mac80211.c b/drivers/net/wireless/iwlwifi/iwl-mac80211.c
index b6805f8..d2be4b6 100644
--- a/drivers/net/wireless/iwlwifi/iwl-mac80211.c
+++ b/drivers/net/wireless/iwlwifi/iwl-mac80211.c
@@ -157,7 +157,8 @@
 	 */
 
 	hw->flags |= IEEE80211_HW_SUPPORTS_PS |
-		     IEEE80211_HW_SUPPORTS_DYNAMIC_PS;
+		     IEEE80211_HW_SUPPORTS_DYNAMIC_PS |
+		     IEEE80211_HW_SCAN_WHILE_IDLE;
 
 	if (hw_params(priv).sku & EEPROM_SKU_CAP_11N_ENABLE)
 		hw->flags |= IEEE80211_HW_SUPPORTS_DYNAMIC_SMPS |