net: tlan: Mark expected switch fall-through

In preparation to enabling -Wimplicit-fallthrough, mark switch cases
where we are expecting to fall through.

Addresses-Coverity-ID: 141440 ("Missing break in switch")
Signed-off-by: NGustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/ti/tlan.c

@@ -966,6 +966,7 @@ static int tlan_ioctl(struct net_device *dev, struct ifreq *rq, int cmd)
 	switch (cmd) {
 	case SIOCGMIIPHY:		/* get address of MII PHY in use. */
 		data->phy_id = phy;
+		/* fall through */
 
 
 	case SIOCGMIIREG:		/* read MII PHY register. */