ath79-nand: (re)add WNDR4300v1

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

(cherry picked from commit bc09b7ec)

docs/user/supported_devices.rst

@@ -142,6 +142,7 @@ ath79-nand
 * Netgear
 
   - WNDR3700 (v4)
+  - WNDR4300 (v1)
 
 ath79-mikrotik
 --------------

targets/ath79-nand

@@ -33,6 +33,10 @@ device('netgear-wndr3700-v4', 'netgear_wndr3700-v4', {
 	},
 })
 
+device('netgear-wndr4300', 'netgear_wndr4300', {
+	factory_ext = '.img',
+})
+
 
 -- ZTE