ARM: dts: imx6q-b850v3: Add switch port configuration

ARM: dts: imx6q-b850v3: Add switch port configuration

This adds support for the Marvell switch and names the network
ports according to the labels, that can be found next to the
connectors ("ID", "IX", "ePort 1", "ePort 2"). The switch is
connected to the host system using a PCI based network card.

The PCI bus configuration has been written using the following
information:

root@b850v3# lspci -tv
-[0000:00]---00.0-[01]----00.0-[02-05]--+-01.0-[03]----00.0  Intel Corporation I210 Gigabit Network Connection
                                        +-02.0-[04]----00.0  Intel Corporation I210 Gigabit Network Connection
                                        \-03.0-[05]--
root@b850v3# lspci -nn
00:00.0 PCI bridge [0604]: Synopsys, Inc. Device [16c3:abcd] (rev 01)
01:00.0 PCI bridge [0604]: PLX Technology, Inc. PEX 8605 PCI Express 4-port Gen2 Switch [10b5:8605] (rev ab)
02:01.0 PCI bridge [0604]: PLX Technology, Inc. PEX 8605 PCI Express 4-port Gen2 Switch [10b5:8605] (rev ab)
02:02.0 PCI bridge [0604]: PLX Technology, Inc. PEX 8605 PCI Express 4-port Gen2 Switch [10b5:8605] (rev ab)
02:03.0 PCI bridge [0604]: PLX Technology, Inc. PEX 8605 PCI Express 4-port Gen2 Switch [10b5:8605] (rev ab)
03:00.0 Ethernet controller [0200]: Intel Corporation I210 Gigabit Network Connection [8086:1533] (rev 03)
04:00.0 Ethernet controller [0200]: Intel Corporation I210 Gigabit Network Connection [8086:1533] (rev 03)

Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.co.uk>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>