net: miiphy: Introduce mdio_init()

Introduce mdio_init() split off from mdio_alloc(), which is used
to initialize already allocated struct mii_dev.

Reviewed-by: Paul Barker <paul.barker.ct@bp.renesas.com>
Signed-off-by: Marek Vasut <marek.vasut+renesas@mailbox.org>
2 files changed