pppoatm: use %*ph to print small buffer

Use %*ph format to print small buffer as hex string.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/atm/pppoatm.c

@@ -216,9 +216,7 @@ static void pppoatm_push(struct atm_vcc *atmvcc, struct sk_buff *skb)
 			pvcc->chan.mtu += LLC_LEN;
 			break;
 		}
-		pr_debug("Couldn't autodetect yet (skb: %02X %02X %02X %02X %02X %02X)\n",
-			 skb->data[0], skb->data[1], skb->data[2],
-			 skb->data[3], skb->data[4], skb->data[5]);
+		pr_debug("Couldn't autodetect yet (skb: %6ph)\n", skb->data);
 		goto error;
 	case e_vc:
 		break;