ath79-generic: (re)add support for UniFi AC Mesh

Gone due to
commit 45c84a117b ("ar71xx: drop target")

docs/user/supported_devices.rst

@@ -84,6 +84,7 @@ ath79-generic
 
 * Ubiquiti
 
+  - UniFi AC Mesh
   - UniFi AP
   - UniFi AP LR
 

package/gluon-core/luasrc/usr/lib/lua/gluon/platform.lua

@@ -34,6 +34,7 @@ function M.is_outdoor_device()
 		'tplink,cpe510-v3',
 		'tplink,eap225-outdoor-v1',
 		'tplink,wbs210-v2',
+		'ubnt,unifiac-mesh',
 	}) then
 		return true
 

targets/ath79-generic

@@ -304,6 +304,11 @@ device('tp-link-wbs210-v2', 'tplink_wbs210-v2')
 
 -- Ubiquiti
 
+device('ubiquiti-unifi-ac-mesh', 'ubnt_unifiac-mesh', {
+	factory = false,
+	packages = ATH10K_PACKAGES_QCA9880,
+})
+
 device('ubiquiti-unifi-ap', 'ubnt_unifi', {
 	aliases = {
 		'ubiquiti-unifi-ap-lr',