iwlwifi: mvm: Don't sleep in RX path

Don't use cancel_delayed_work_sync() inside the channel switch
notifications as they are handled synchronously as part of the RX path.
Fix that by replacing it with cancel_delayed_work(). This should be safe
as we don't really care whether the work is already started and in such
case we would disconnect anyway.
Signed-off-by: Andrei Otcheretianski <andrei.otcheretianski@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>

drivers/net/wireless/intel/iwlwifi/mvm/mac-ctxt.c

@@ -1570,7 +1570,7 @@ void iwl_mvm_channel_switch_noa_notif(struct iwl_mvm *mvm,
 		return;
 	case NL80211_IFTYPE_STATION:
 		iwl_mvm_csa_client_absent(mvm, vif);
-		cancel_delayed_work_sync(&mvmvif->csa_work);
+		cancel_delayed_work(&mvmvif->csa_work);
 		ieee80211_chswitch_done(vif, true);
 		break;
 	default:

drivers/net/wireless/intel/iwlwifi/mvm/time-event.c

@@ -234,7 +234,7 @@ iwl_mvm_te_handle_notify_csa(struct iwl_mvm *mvm,
 			break;
 		}
 		iwl_mvm_csa_client_absent(mvm, te_data->vif);
-		cancel_delayed_work_sync(&mvmvif->csa_work);
+		cancel_delayed_work(&mvmvif->csa_work);
 		ieee80211_chswitch_done(te_data->vif, true);
 		break;
 	default: