realtek: dts: add pcs-handle to switch ports

realtek: dts: add pcs-handle to switch ports

For all switch ports where the assigned SerDes is known, add the new
pcs-handle to the dts. Leave the existing <sds> assignments to the
PHYs as is because the driver has not yet been updated.

Signed-off-by: Markus Stockhausen <[email protected]>
Link: https://github.com/openwrt/openwrt/pull/20111
Signed-off-by: Robert Marko <[email protected]>