aspeed: add support for the Aspeed MII controller of the AST2600

The AST2600 SoC has an extra controller to set the PHY registers.

Signed-off-by: Cédric Le Goater <clg@kaod.org>
Reviewed-by: Joel Stanley <joel@jms.id.au>
Message-id: 20190925143248.10000-23-clg@kaod.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
4 files changed