rtl838x: add new architecture

rtl838x: add new architecture

This adds support for the RTL838x Architecture.
SoCs of this type are used in managed and un-managed Switches and Routers
with 8-28 ports. Drivers are provided for SoC initialization, GPIOs, Flash,
Ethernet including a DSA switch driver and internal and external PHYs used
with these switches.

Supported SoCs:

	RTL8380M
	RTL8381M
	RTL8382M

The kernel will also boot on the following RTL839x SoCs, however driver
support apart from spi-nor is missing:

	RTL8390
	RTL8391
	RTL8393

The following PHYs are supported:

	RTL8214FC (Quad QSGMII multiplexing GMAC and SFP port)
	RTL8218B internal: internal PHY of the RTL838x chips
	RTL8318b external (QSGMII 8-port GMAC phy)
	RTL8382M SerDes for 2 SFP ports
	Initialization sequences for the PHYs are provided in the form of
	firmware files.

Flash driver supports 3 / 4 byte access

DSA switch driver supports VLANs, port isolation, STP and port mirroring.

The ALLNET ALL-SG8208M is supported as Proof of Concept:

	RTL8382M SoC
	1 MIPS 4KEc core @ 500MHz
	8 Internal PHYs (RTL8218B)
	128MB DRAM (Nanya NT5TU128MB)
	16MB NOR Flash (MXIC 25L128)
	8 GBEthernet ports with one green status LED each (SoC controlled)
	1 Power LED (not configurable)
	1 SYS LED (configurable)
	1 On-Off switch (not configurable)
	1 Reset button at the right behind right air-vent (not configurable)
	1 Reset button on front panel (configurable)
	12V 1A barrel connector
	1 serial header with populated standard pin connector and with markings
	  GND TX RX Vcc(3.3V), connection properties: 115200 8N1

To install, upload the sysupgrade image to the OEM webpage.

Signed-off-by: Birger Koblitz <git@birger-koblitz.de>