ath79-nand: (re)add WNDR3700v4

Gone due to
commit 45c84a11 ("ar71xx: drop target")

docs/user/supported_devices.rst

@@ -134,6 +134,10 @@ ath79-nand
   - GL-AR300M
   - GL-AR750S
 
+* Netgear
+
+  - WNDR3700 (v4)
+
 ath79-mikrotik
 --------------
 

targets/ath79-nand

@@ -17,3 +17,13 @@ device('gl.inet-gl-ar750s-nor', 'glinet_gl-ar750s-nor', {
 	factory = false,
 	packages = ATH10K_PACKAGES_QCA9887,
 })
+
+
+-- Netgear
+
+device('netgear-wndr3700-v4', 'netgear_wndr3700-v4', {
+	factory_ext = '.img',
+	manifest_aliases = {
+		'netgear-wndr3700v4', -- Upgrade from OpenWrt 19.07
+	},
+})