Re-implement the Marvell Kirkwood ts41x-setup.c in DT.

As with the QNAP 119, there are two variants, depending on which SoC
has been used. They differ on Ethernet PHY addresses and number of
PCIe busses.
Signed-off-by: NAndrew Lunn <andrew@lunn.ch>
Tested-by: Ian Campbell <ijc@hellion.org.uk> (kirkwood-ts419-6281.dtb)
Signed-off-by: NJason Cooper <jason@lakedaemon.net>