net: dsa: sja1105: provide own phylink MAC operations

Convert sja1105 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: Florian Fainelli <florian.fainelli@broadcom.com>
Link: https://lore.kernel.org/r/E1rvIcT-006bQW-S3@rmk-PC.armlinux.org.uk


Signed-off-by: Paolo Abeni <pabeni@redhat.com>