net: mdio: Add ACPI support code for mdio

commit a7b891ab10f2108a3a9cad4570532f8acc3f03da from
git://source.codeaurora.org/external/qoriq/qoriq-components/linux



Define acpi_mdiobus_register() to Register mii_bus and create PHYs for
each ACPI child node.

Signed-off-by: Calvin Johnson <calvin.johnson@oss.nxp.com>
Signed-off-by: Ioana Ciornei <ioana.ciornei@nxp.com>
Acked-by: Rafael J. Wysocki <rafael@kernel.org>
Acked-by: Grant Likely <grant.likely@arm.com>
(cherry picked from commit 0f9ed0ba0feb2ed0ad4d491bf7b2ea0dc3d815d2)
Signed-off-by: Meng Li <Meng.Li@windriver.com>