drivers/net/ethernet/nxp/lpc_eth.c: Call mdiobus_unregister before mdiobus_free

drivers/net/ethernet/nxp/lpc_eth.c: Call mdiobus_unregister before mdiobus_free

Based on commit b27393aecf66199f5ddad37c302d3e0cfadbe6c0

Calling mdiobus_free without calling mdiobus_unregister causes
BUG_ON(). This patch fixes the issue.

The semantic patch that found this issue(http://coccinelle.lip6.fr/):
// <smpl>
@@
expression E;
@@
  ... when != mdiobus_unregister(E);

+ mdiobus_unregister(E);
  mdiobus_free(E);
// </smpl>

Signed-off-by: Peter Senna Tschudin <[email protected]>
Tested-by: Roland Stigge <[email protected]>
Tested-by: Alexandre Pereira da Silva <[email protected]>
Signed-off-by: David S. Miller <[email protected]>