mac802154: fix following checkpath.pl warning Prefer pr_warn(... to pr_warning(...

This patch fixes checkpath.pl:
 WARNING: Prefer pr_warn(... to pr_warning(...
 #447: FILE: ./wpan.c:447:

Signed-off-by: Weilong Chen <chenweilong@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/mac802154/wpan.c b/net/mac802154/wpan.c
index e24bcf9..372d8a2 100644
--- a/net/mac802154/wpan.c
+++ b/net/mac802154/wpan.c
@@ -444,8 +444,8 @@
 	case IEEE802154_FC_TYPE_DATA:
 		return mac802154_process_data(sdata->dev, skb);
 	default:
-		pr_warning("ieee802154: bad frame received (type = %d)\n",
-			   mac_cb_type(skb));
+		pr_warn("ieee802154: bad frame received (type = %d)\n",
+			mac_cb_type(skb));
 		kfree_skb(skb);
 		return NET_RX_DROP;
 	}