ramips: add support for I-O DATA WN-GX300GR

I-O DATA WN-GX300GR is a 2.4 GHz band 11n router, based on MediaTek
MT7621S.

Specification:

- MT7621S (1-Core, 2-Threads)
- 64 MB of RAM
- 8 MB of Flash (SPI)
- 2T2R 2.4 GHz
- 5x 10/100/1000 Mbps Ethernet
- 2x LEDs, 4x keys (2x buttons, 1x slide switch)
- UART header on PCB
  - Vcc, GND, TX, RX from ethernet port side
  - baudrate: 115200 bps (U-Boot, OpenWrt)

Flash instruction using initramfs image:

1. Connect serial cable to UART header
2. Rename OpenWrt initramfs image for WN-GX300GR to "uImageWN-GX300GR"
and place it in the TFTP directory
3. Set the IP address of the computer to 192.168.99.8, connect to the
LAN port of WN-GX300GR, and start the TFTP server on the computer
4. Connect power cable to WN-GX300GR and turn on the router
5. Press "1" key on the serial console to interrupt boot process on
U-Boot, press Enter key 3 times and start firmware download via TFTP
6. WN-GX300GR downloads initramfs image and boot with it
7. On the initramfs image, execute "mtd erase firmware" to erase stock
firmware and execute sysupgrade with sysupgrade image for WN-GX300GR
8. Wait ~150 seconds to complete flasing

Signed-off-by: INAGAKI Hiroshi <musashino.open@gmail.com>

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

@@ -168,6 +168,7 @@ dlink,dwr-921-c1)
 	ucidef_set_led_default "sigstrength" "Signal Strength" "$boardname:green:sigstrength" "0"
 	;;
 dir-810l|\
+iodata,wn-gx300gr|\
 mzk-750dhp|\
 mzk-dp150n|\
 vr500)

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

@@ -194,6 +194,7 @@ ramips_setup_interfaces()
 	gl-mt300n|\
 	gl-mt750|\
 	hg255d|\
+	iodata,wn-gx300gr|\
 	jhr-n805r|\
 	jhr-n825r|\
 	jhr-n926r|\
@@ -459,6 +460,9 @@ ramips_setup_macs()
 		[ -n "$lan_mac" ] || lan_mac=$(cat /sys/class/net/eth0/address)
 		wan_mac=$(macaddr_add "$lan_mac" 1)
 		;;
+	iodata,wn-gx300gr)
+		wan_mac=$(macaddr_add "$(mtd_get_mac_binary Factory 4)" 1)
+		;;
 	kn_rc|\
 	kn_rf|\
 	kng_rc)

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

@@ -27,6 +27,7 @@ get_status_led() {
 	fonera20n|\
 	firewrt|\
 	hg255d|\
+	iodata,wn-gx300gr|\
 	kn|\
 	kn_rc|\
 	kn_rf|\

target/linux/ramips/base-files/lib/upgrade/platform.sh

@@ -75,6 +75,7 @@ platform_check_image() {
 	hpm|\
 	ht-tm02|\
 	hw550-3g|\
+	iodata,wn-gx300gr|\
 	ip2202|\
 	jhr-n805r|\
 	jhr-n825r|\