net: dsa: mt7530: Convert to PHYLINK API

Convert mt7530 to PHYLINK API

Signed-off-by: René van Dorst <opensource@vdorst.com>
Tested-by: Frank Wunderlich <frank-w@public-files.de>
Acked-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>