mac80211: fix GFP_KERNEL under tasklet context

cfg80211_sta_opmode_change_notify needs a gfp_t flag to hint the nl80211
stack when allocating new skb, but it is called under tasklet context
here with GFP_KERNEL and kernel will yield a warning about it.

Cc: stable@vger.kernel.org
Fixes: ff84e7bfe176 ("mac80211: Add support to notify ht/vht opmode modification.")
Signed-off-by: Yan-Hsuan Chuang <yhchuang@realtek.com>
ACKed-by: Larry Finger <Larry.Finger@lwfinger.net>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

net/mac80211/rx.c

@@ -3063,7 +3063,7 @@ ieee80211_rx_h_action(struct ieee80211_rx_data *rx)
 			cfg80211_sta_opmode_change_notify(sdata->dev,
 							  rx->sta->addr,
 							  &sta_opmode,
-							  GFP_KERNEL);
+							  GFP_ATOMIC);
 			goto handled;
 		}
 		case WLAN_HT_ACTION_NOTIFY_CHANWIDTH: {
@@ -3100,7 +3100,7 @@ ieee80211_rx_h_action(struct ieee80211_rx_data *rx)
 			cfg80211_sta_opmode_change_notify(sdata->dev,
 							  rx->sta->addr,
 							  &sta_opmode,
-							  GFP_KERNEL);
+							  GFP_ATOMIC);
 			goto handled;
 		}
 		default: