ucc_geth: fix section mismatch

This fix section mismatch:
reference to .exit.text:uec_mdio_exit (between 'ucc_geth_init' and 'uec_mdio_init')

void __exit uec_mdio_exit(void) is called from
- static int __init ucc_geth_init(void)
- static void __exit ucc_geth_exit(void)

First one would make error path more than just an error.

Signed-off-by: Domen Puncer <domen.puncer@telargo.com>
Signed-off-by: Li Yang <leoli@freescale.com>