net: phy: meson-gxl: enable edpd tunable support for G12A internal PHY

Enable EDPD PHY tunable support for the G12A internal PHY, reusing the
recently added tunable support in the smsc driver.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Acked-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Link: https://lore.kernel.org/r/8d309575-067c-7321-33cf-6ffac11f7c8d@gmail.com


Signed-off-by: Jakub Kicinski <kuba@kernel.org>