ramips: add support for the HNET C108

The HNET C108
(http://www.szhwtech88.com/Product-product-cid-100-id-4374.html) is a
mifi based on MT7602A, which has the following specifications:

* CPU: MT7620A
* 1x 10/100Mbps Ethernet.
* 16 MB Flash.
* 64 MB RAM.
* 1x USB 2.0 port. Only power is connected, this port is meant for
charging other devices.
* 1x mini-PCIe slots.
* 1x SIM slots.
* 1x 2.4Ghz WIFI.
* 1x button.
* 6000 mAh battery.
* 5x controllable LEDs.

Works:
* Wifi.
* Switch.
* mini-PCIe slot. Only tested with a USB device (a modem).
* SIM slot.
* Sysupgrade.
* Button (reset).

Not working (also applies to the factory firmware):
* Wifi LED. It is always switched on, there is no relation to the
up/down state or activity of the wireless interface.

Not tested:
* SD card reader.

Notes:
* The C108 has no dedicated status LED. I therefore set the LAN LED as
status LED.

Installation:
The router comes pre-installed with OpenWRT, including a variant of
Luci. The initial firmware install can be done through this UI,
following normal procedure. I.e., access the UI and update the firmware
using the sysupgrade-image. Remember to select that you do not want to
keep existing settings.

Recovery:
If you brick the device, the C108 supports recovery using TFTP. Keep the
reset button pressed for ~5sec when booting to trigger TFTP. Set the
address of the network interface on your machine to 10.10.10.3/24, and
rename your image file to Kernal.bin.

Signed-off-by: Kristian Evensen <kristian.evensen@gmail.com>

target/linux/ramips/base-files/etc/board.d/01_leds

@@ -82,6 +82,10 @@ broadway)
 	set_usb_led "$board:red:diskmounted"
 	set_wifi_led "$board:red:wps_active"
 	;;
+c108)
+	ucidef_set_led_netdev "lan" "lan" "$board:green:lan" "eth0"
+	ucidef_set_led_netdev "modem" "modem" "$board:green:modem" "wwan0"
+	;;
 c20i)
 	ucidef_set_led_switch "lan" "lan" "$board:blue:lan" "switch0" "0x1e"
 	ucidef_set_led_switch "wan" "wan" "$board:blue:wan" "switch0" "0x01"

target/linux/ramips/base-files/etc/board.d/02_network

@@ -217,6 +217,7 @@ ramips_setup_interfaces()
 		ucidef_add_switch "switch0" \
 			"1:lan" "2:lan" "3:lan" "4:lan" "0:wan" "9@eth0"
 		;;
+	c108|\
 	cf-wr800n)
 		ucidef_add_switch "switch0" \
 			"4:lan" "6t@eth0"

target/linux/ramips/base-files/etc/diag.sh

@@ -103,6 +103,9 @@ get_status_led() {
 	wrh-300cr)
 		status_led="$board:green:wps"
 		;;
+	c108)
+		status_led="$board:green:lan"
+		;;
 	cf-wr800n|\
 	psg1208)
 		status_led="$board:white:wps"