caif-hsi: Set default MTU to 4096

Default MTU for CAIF HSI was wrongly set to 15 * 4092 bytes.
The patch sets default MTU size to 4096.
Signed-off-by: Sjur Brændeland <sjur.brandeland@stericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/caif/caif_hsi.c

@@ -978,7 +978,7 @@ static void cfhsi_setup(struct net_device *dev)
 	dev->netdev_ops = &cfhsi_ops;
 	dev->type = ARPHRD_CAIF;
 	dev->flags = IFF_POINTOPOINT | IFF_NOARP;
-	dev->mtu = CFHSI_MAX_PAYLOAD_SZ;
+	dev->mtu = CFHSI_MAX_CAIF_FRAME_SZ;
 	dev->tx_queue_len = 0;
 	dev->destructor = free_netdev;
 	skb_queue_head_init(&cfhsi->qhead);