ar71xx-generic: add profile for UBNT Airgateway Pro and alias for UBNT Airgateway LR (#1107)

The Airgateway LR is the same device as the normal Airgateway but with an detachable antenna. The Pro version is a cheap dual band device.

docs/index.rst

@@ -196,6 +196,8 @@ ar71xx-generic
 * Ubiquiti
 
   - Air Gateway
+  - Air Gateway LR
+  - Air Gateway PRO
   - Air Router
   - Bullet M2/M5
   - Loco M2/M5

targets/ar71xx-generic

@@ -189,6 +189,10 @@ fi
 # Ubiquiti
 
 device ubiquiti-airgateway ubnt-air-gateway
+alias ubiquiti-airgateway-lr
+
+device ubiquiti-airgateway-pro ubnt-air-gateway-pro
+
 device ubiquiti-airrouter ubnt-airrouter
 
 device ubiquiti-bullet-m ubnt-bullet-m