iwlwifi: mvm: use atomic interface iteration to avoid deadlock

Using the non-atomic version creates a dependency between
mac80211's iflist_mtx and mvm->mutex. Use the atomic version
instead which doesn't take iflist_mtx but can't sleep, so
send the HCMD in ASYNC.
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

drivers/net/wireless/iwlwifi/mvm/mac80211.c

@@ -475,7 +475,7 @@ static int iwl_mvm_mac_add_interface(struct ieee80211_hw *hw,
 	if (mvm->vif_count > 1) {
 		IWL_DEBUG_MAC80211(mvm,
 				   "Disable power on existing interfaces\n");
-		ieee80211_iterate_active_interfaces(
+		ieee80211_iterate_active_interfaces_atomic(
 					    mvm->hw,
 					    IEEE80211_IFACE_ITER_NORMAL,
 					    iwl_mvm_pm_disable_iterator, mvm);

drivers/net/wireless/iwlwifi/mvm/power.c

@@ -194,7 +194,7 @@ int iwl_mvm_power_disable(struct iwl_mvm *mvm, struct ieee80211_vif *vif)
 			cmd.id_and_color, iwlmvm_mod_params.power_scheme,
 			le16_to_cpu(cmd.flags));
 
-	return iwl_mvm_send_cmd_pdu(mvm, POWER_TABLE_CMD, CMD_SYNC,
+	return iwl_mvm_send_cmd_pdu(mvm, POWER_TABLE_CMD, CMD_ASYNC,
 				    sizeof(cmd), &cmd);
 }