net: dsa: vsc73xx: convert to PHYLINK

This patch replaces the adjust_link api with the phylink apis that provide
equivalent functionality.

The remaining functionality from the adjust_link is now covered in the
mac_link_* and mac_config from phylink_mac_ops structure.

Removes:
.adjust_link
Adds phylink_mac_ops structure:
.mac_config
.mac_link_up
.mac_link_down

Signed-off-by: Pawel Dembicki <paweldembicki@gmail.com>
Link: https://lore.kernel.org/r/20240417205048.3542839-3-paweldembicki@gmail.com


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