arm: mvebu: eDPU: support new board revision

There is a new eDPU revision that uses Marvell 88E6361 switch onboard.
We can rely on detecting the switch to enable and fixup the Linux DTS
so a single DTS can be used.

There is currently no support for the 88E6361 switch and thus no working
networking in U-Boot, so we disable both ports.

Signed-off-by: Robert Marko <robert.marko@sartura.hr>
Reviewed-by: Stefan Roese <sr@denx.de>