ar71xx: fix sysupgrade to ath79 for wndr3700v2 and wndr3800

ar71xx has just one board name wndr3700 for wndr 3700, 3700v2 and 3800
which is causing issues with sysupgrades to ath79 as there are separate
images for every board, so fix it by using proper board name on ar71xx
as well.

Ref: FS#2510
Signed-off-by: Petr Štetiar <ynezz@true.cz>

target/linux/ar71xx/base-files/etc/board.d/01_leds

@@ -999,7 +999,9 @@ wam250)
 wndap360)
 	ucidef_set_led_power "power" "POWER GREEN" "netgear:green:power" "1"
 	;;
-wndr3700)
+wndr3700|\
+wndr3700v2|\
+wndr3800)
 	ucidef_set_led_default "wan" "WAN LED (green)" "netgear:green:wan" "0"
 	ucidef_set_led_usbport "usb" "USB" "netgear:green:usb" "usb1-port1"
 	;;

target/linux/ar71xx/base-files/etc/diag.sh

@@ -527,7 +527,9 @@ get_status_led() {
 	r6100|\
 	wndap360|\
 	wndr3700|\
+	wndr3700v2|\
 	wndr3700v4|\
+	wndr3800|\
 	wndr4300|\
 	wnr2000|\
 	wnr2000-v3|\

target/linux/ar71xx/base-files/etc/uci-defaults/04_led_migration

@@ -60,6 +60,8 @@ oolite-v1)
 	;;
 wndap360|\
 wndr3700|\
+wndr3700v2|\
+wndr3800|\
 wnr2000|\
 wnr2200)
 	migrate_leds "${board}:=netgear:"

target/linux/ar71xx/base-files/lib/ar71xx.sh

@@ -46,13 +46,16 @@ wndr3700_board_detect() {
 				machine="NETGEAR WNDRMAC"
 			else
 				machine="NETGEAR WNDR3700v2"
+				name="wndr3700v2"
 			fi
 			;;
 		'29763654+16+64'*)
 			machine="NETGEAR ${model_stripped:14}"
+			name="wndr3700v2"
 			;;
 		'29763654+16+128'*)
 			machine="NETGEAR ${model_stripped:15}"
+			name="wndr3800"
 			;;
 		*)
 			# Unknown ID

target/linux/ar71xx/base-files/lib/upgrade/platform.sh

@@ -677,6 +677,8 @@ platform_check_image() {
 		return 1
 		;;
 	wndr3700|\
+	wndr3700v2|\
+	wndr3800|\
 	wnr1000-v2|\
 	wnr2000-v3|\
 	wnr612-v2|\