ramips: add support for minew g1-c

ramips: add support for minew g1-c

The minew g1-c is a smart home gateway / BLE gateway.
A Nordic nRF52832 is available via USB UART (cp210x) to support BLE.
The LED ring is a ring of 24x ws2812b connect to a generic GPIO (unsupported).
There is a small LED which is only visible when the device is open which
will be used as LED until the ws2812b is supported.
The board has also a micro sdcard/tfcard slot (untested).
The Nordic nRF52832 exposes SWD over a 5pin header (GND, VCC, SWD, SWC, RST).
The vendor uses an older OpenWrt version, sysupgrade can be used via
serial or ssh.

CPU:		MT7628AN / 580MHz
RAM:		DDR2 128 MiB RAM
Flash:		SPI NOR 16 MiB W25Q128
Ethernet:	1x 100 mbit (Port 0) (PoE in)
USB:		USB hub, 2x external, 1x internal to USB UART
Power:		via micro usb or PoE 802.11af
UART:		3.3V, 115200 8n1

Signed-off-by: Alexander Couzens <lynxis@fe80.eu>