phy: phy-bcm-ns-usb3: drop support for deprecated DT binding

Initially this PHY driver was implementing MDIO access on its own. It
was caused by lack of proper hardware design understanding.

It has been changed back in 2017. DT bindings were changed and driver
was updated to use MDIO layer.

It should be really safe now to drop the old deprecated code. All Linux
stored DT files don't use it for 3,5 year. There is close to 0 chance
there is any bootloader with its own DTB using old the binding.

Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
Acked-by: Florian Fainelli <f.fainelli@gmail.com>
Link: https://lore.kernel.org/r/20201113113423.9466-1-zajec5@gmail.com


Signed-off-by: Vinod Koul <vkoul@kernel.org>