ramips: add support for Lava LR-25G001

The Lava LR-25G001 Wireless Router is based on the MT7620A SoC.

Specification:

- MediaTek MT7620A (580 Mhz)
- 64 MB of RAM
- 16 MB of FLASH
- 1x 802.11bgn radio
- 1x 802.11ac radio (MT7610EN)
- 5x 10/100/1000 Mbps AR8337 Switch (1 WAN AND 4 LAN)
- 2x external, detachable antennas
- 1x USB 2.0
- UART (J3) header on PCB (57600 8n1)
- 8x LED (3x GPIO-controlled), 2x button
- JBOOT bootloader

Known issues:
- Work only three Gigabit ports (3/5, 1 WAN and 2LAN)

Installation:
Apply factory image via http web-gui or JBOOT recovery page

How to revert to OEM firmware:
- push the reset button and turn on the power. Wait until LED start
  blinking (~10sec.)
- upload original factory image via JBOOT http (IP: 192.168.123.254)

Signed-off-by: Pawel Dembicki <paweldembicki@gmail.com>

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

@@ -295,7 +295,8 @@ platform_check_image() {
 	dlink,dwr-116-a1|\
 	dlink,dwr-118-a2|\
 	dlink,dwr-921-c1|\
-	dwr-512-b)
+	dwr-512-b|\
+	lava,lr-25g001)
 		[ "$magic" != "0404242b" ] && {
 			echo "Invalid image type."
 			return 1