ramips: add support for Asus RT-N11P / RT-N12+ / RT-N12E b1

This is a variant of the MT7620N-based Asus routers.

Specifications:

- MT7620N (580 MHz)
- 32 MB RAM
- 8 MB Flash
- 5x 10/100Mbps Ethernet (built-in switch)
- 2.4 GHz WLAN
- 2x external, non-detachable antennas
- UART (J2) header on PCB (115200 8n1)

Flash instructions:

1. Configure PC with static IP 192.168.1.75/24
2. Connect PC with one of LAN ports, press the reset button, power up
   the router and keep button pressed for around 6-7 seconds. All 4 LEDs will
   start to blink, which is when the router will accept firmware files via TFTP.
   No known limitations on firmware filenames, just send it with a TFTP client
   to 192.168.1.1.
3. Router will download file from server, write it to flash and reboot.

Signed-off-by: Zoltan HERPAI <wigyori@uid0.hu>

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

@@ -340,6 +340,12 @@ rt-ac51u)
 	set_wifi_led "$board:blue:wifi"
 	set_usb_led "$board:blue:usb" "1-1"
 	;;
+rt-n12p)
+	ucidef_set_led_default "power" "power" "$board:green:power" "1"
+	ucidef_set_led_netdev "lan" "lan" "$board:green:lan" eth0.1
+	ucidef_set_led_netdev "wan" "wan" "$board:green:wan" eth0.2
+	set_wifi_led "$board:green:air"
+	;;
 rt-n14u)
 	ucidef_set_led_default "power" "power" "$board:blue:power" "1"
 	ucidef_set_led_netdev "lan" "lan" "$board:blue:lan" eth0.1

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

@@ -100,6 +100,7 @@ ramips_setup_interfaces()
 	psg1208|\
 	psg1218a|\
 	r6220|\
+	rt-n12p)
 	sap-g3200u3|\
 	sk-wb8|\
 	u7621-06-256M-16M|\

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

@@ -460,6 +460,9 @@ ramips_board_detect() {
 	*"RT-N10+")
 		name="rt-n10-plus"
 		;;
+	*"RT-N12+")
+		name="rt-n12p"
+		;;
 	*"RT-N13U")
 		name="rt-n13u"
 		;;

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

@@ -130,6 +130,7 @@ platform_check_image() {
 	rt-ac51u|\
 	rt-g32-b1|\
 	rt-n10-plus|\
+	rt-n12p|\
 	rt-n13u|\
 	rt-n14u|\
 	rt-n15|\