mediatek: fix DTS defining mt7530 switch phys but not referencing them

mediatek: fix DTS defining mt7530 switch phys but not referencing them

The upstream solution to define the MDIO bus in DT is a bit
more strict than our previous downstream solution doing the same thing
and now requires switch PHYs to be referenced in DT as well.

Arınç Ünal told us in #15141:
"With [the now upstream patch written by him which we backported], the
switch MDIO bus won't be assigned to ds->user_mii_bus when the switch
MDIO bus is defined on the device tree anymore. This was not the case
with the downstream patch.

When ds->user_mii_bus is populated, DSA will 1:1 map the port with
PHY. Meaning port with address 1 will be mapped to PHY with address 1.
Because that ds->user_mii_bus is not populated when the switch MDIO
bus is defined on the device tree, on every port node, the PHY address
must be supplied by the phy-handle property."

Add those phy-handles to affected devices' DT.

Fixes: 4354b34f6f ("generic: 6.6: sync mt7530 DSA driver with upstream")
Fixes: 401a6ccfaf ("generic: 6.1: sync mt7530 DSA driver with upstream")
Signed-off-by: Daniel Golle <daniel@makrotopia.org>