net: pcs: Drop the TSE PCS driver

Now that we can easily create a mdio-device that represents a
memory-mapped device that exposes an MDIO-like register layout, we don't
need the Altera TSE PCS anymore, since we can use the Lynx PCS instead.

Reviewed-by: Simon Horman <simon.horman@corigine.com>
Signed-off-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
Signed-off-by: David S. Miller <davem@davemloft.net>