net: ethernet: mtk_eth_soc: drop clocks unused by Ethernet driver

net: ethernet: mtk_eth_soc: drop clocks unused by Ethernet driver

Clocks for SerDes and PHY are going to be handled by standalone drivers
for each of those hardware components. Drop them from the Ethernet driver.

The clocks which are being removed for this patch are responsible for
the for the SerDes PCS and PHYs used for the 2nd and 3rd MAC which are
anyway not yet supported. Hence backwards compatibility is not an issue.

Signed-off-by: Daniel Golle <daniel@makrotopia.org>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Link: https://patch.msgid.link/b5faaf69b5c6e3e155c64af03706c3c423c6a1c9.1722335682.git.daniel@makrotopia.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>