fsl-mc: Update dependencies for DM_ETH

fsl-mc: Update dependencies for DM_ETH

When using DM_ETH, which should be the default now, we need to always
have DM_MDIO and FSL_LS_MDIO enabled, so select them.

Cc: Priyanka Jain <priyanka.jain@nxp.com>
Cc: Rajesh Bhagat <rajesh.bhagat@nxp.com>
Cc: Wasim Khan <wasim.khan@nxp.com>
Cc: Udit Agarwal <udit.agarwal@nxp.com>
Cc: Ashish Kumar <Ashish.Kumar@nxp.com>
Cc: Meenakshi Aggarwal <meenakshi.aggarwal@nxp.com>
Cc: Patrick Delaunay <patrick.delaunay@foss.st.com>
Cc: Patrice Chotard <patrice.chotard@foss.st.com>
Cc: Manish Tomar <Manish.Tomar@nxp.com>
Signed-off-by: Tom Rini <trini@konsulko.com>