netdev: Remove redundant checks for CAP_NET_ADMIN in MDIO implementations

dev_ioctl() already checks capable(CAP_NET_ADMIN) before calling the
driver's implementation of MDIO ioctls.

Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/natsemi.c

@@ -3075,8 +3075,6 @@ static int netdev_ioctl(struct net_device *dev, struct ifreq *rq, int cmd)
 		return 0;
 
 	case SIOCSMIIREG:		/* Write MII PHY register. */
-		if (!capable(CAP_NET_ADMIN))
-			return -EPERM;
 		if (dev->if_port == PORT_TP) {
 			if ((data->phy_id & 0x1f) == np->phy_addr_external) {
  				if ((data->reg_num & 0x1f) == MII_ADVERTISE)