net: stmmac: sun8i: Remove the compatibles

Since the bindings have been controversial, and we follow the DT stable ABI
rule, we shouldn't let a driver with a DT binding that might change slip
through in a stable release.

Remove the compatibles to make sure the driver will not probe and no-one
will start using the binding currently implemented. This commit will
obviously need to be reverted in due time.

Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: David S. Miller <davem@davemloft.net>