net/hamradio/6pack: remove redundant check in sp_encaps()

"len > sp->mtu" checked twice in a row in sp_encaps().
Remove the second check.
Signed-off-by: NDenis Efremov <efremov@linux.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/hamradio/6pack.c

@@ -171,11 +171,6 @@ static void sp_encaps(struct sixpack *sp, unsigned char *icp, int len)
 		goto out_drop;
 	}
 
-	if (len > sp->mtu) {	/* sp->mtu = AX25_MTU = max. PACLEN = 256 */
-		msg = "oversized transmit packet!";
-		goto out_drop;
-	}
-
 	if (p[0] > 5) {
 		msg = "invalid KISS command";
 		goto out_drop;