net: dsa: felix: provide own phylink MAC operations

Convert felix to provide its own phylink MAC operations, thus
avoiding the shim layer in DSA's port.c.

Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Reviewed-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Tested-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Link: https://lore.kernel.org/r/E1sByYA-00EM0y-Jn@rmk-PC.armlinux.org.uk


Signed-off-by: Jakub Kicinski <kuba@kernel.org>