ramips-mt7621: add support for Xiaomi Mi Router 4a Gigabit Edition v2 (#3293)

(cherry picked from commit b50007d1)

docs/user/supported_devices.rst

@@ -462,7 +462,7 @@ ramips-mt7621
 * Xiaomi
 
   - Xiaomi Mi Router 3G (v1, v2)
-  - Xiaomi Mi Router 4A (Gigabit Edition v1)
+  - Xiaomi Mi Router 4A (Gigabit Edition v1, v2)
 
 * ZBT
 

targets/ramips-mt7621

@@ -120,6 +120,10 @@ device('xiaomi-mi-router-4a-gigabit-edition', 'xiaomi_mi-router-4a-gigabit', {
 	factory = false,
 })
 
+device('xiaomi-mi-router-4a-gigabit-edition-v2', 'xiaomi_mi-router-4a-gigabit-v2', {
+	factory = false,
+})
+
 device('xiaomi-mi-router-3g', 'xiaomi_mi-router-3g', {
 	factory = false,
 })