net: dsa: microchip: update the ksz_phylink_get_caps

This patch assigns the phylink_get_caps in ksz8795 and ksz9477 to
ksz_phylink_get_caps. And update their mac_capabilities in the
respective ksz_dev_ops.

Signed-off-by: Arun Ramadoss <arun.ramadoss@microchip.com>
Reviewed-by: Vladimir Oltean <olteanv@gmail.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>