phy: adin: add driver for Analog Devices ADIN1300 PHY

The current implementation configures RGMII using device tree phy-mode
property and then calls genphy_config

adin_config_rgmii_mode is derived from:
https://github.com/varigit/linux-imx/blob/lf-5.10.y_var04/drivers/net/phy/adin.c#L218-L262



Signed-off-by: Nate Drude <nate.d@variscite.com>
Reviewed-by: Ramon Fried <rfried.dev@gmail.com>