net: emaclite: Fix position of lp->mii_bus assignment

To ensure MDIO bus is not double freed in remove() path
assign lp->mii_bus after MDIO bus registration.

Signed-off-by: Radhey Shyam Pandey <radhey.shyam.pandey@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>