x25: use %*ph to print small buffer

Use %*ph format to print small buffer as hex string.
Suggested-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: NAntonio Cardace <anto.cardace@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/x25/x25_subr.c

@@ -335,8 +335,7 @@ int x25_decode(struct sock *sk, struct sk_buff *skb, int *ns, int *nr, int *q,
 		}
 	}
 
-	pr_debug("invalid PLP frame %02X %02X %02X\n",
-	       frame[0], frame[1], frame[2]);
+	pr_debug("invalid PLP frame %3ph\n", frame);
 
 	return X25_ILLEGAL;
 }