ramips-mt7621: add Xiaomi Mi Router 3G

Co-authored-by: Jan-Niklas Burfeind <git@aiyionpri.me>
fixed commit title

(cherry picked from commit 84a76af8)

docs/user/supported_devices.rst

@@ -387,7 +387,7 @@ ramips-mt7621
 * Xiaomi
 
   - Xiaomi Mi Router 4A (Gigabit Edition)
-  - Xiaomi Mi Router 3G v2
+  - Xiaomi Mi Router 3G (v1, v2)
 
 ramips-mt76x8
 -------------

targets/ramips-mt7621

@@ -80,10 +80,13 @@ device('xiaomi-mi-router-4a-gigabit-edition', 'xiaomi_mi-router-4a-gigabit', {
 	factory = false,
 })
 
-device('xiaomi-mi-router-3g-v2', 'xiaomi_mi-router-3g-v2', {
+device('xiaomi-mi-router-3g', 'xiaomi_mi-router-3g', {
 	factory = false,
 })
 
+device('xiaomi-mi-router-3g-v2', 'xiaomi_mi-router-3g-v2', {
+	factory = false,
+})
 
 -- ZBT