ar71xx: add model detection for UniFi AC-LR

This commit adds correct model detection for UniFi
AC-LR. Previously, said device was incorrectly detected
as UniFi-AC-LITE/MESH.

The Information about the device is stored at 0xC in the EEPROM
partition. It corresponds to the sysid in /etc/board.info of the
Ubiquiti stock firmware.

Signed-off-by: Andreas Ziegler <dev@andreas-ziegler.de>
[adjust naming style of target to existing ones]
Signed-off-by: David Bauer <mail@david-bauer.net>
(cherry picked from commit 2bc7c519dcc0e7ca09feed24a3b9a105bc49f423)
Signed-off-by: David Bauer <mail@david-bauer.net>

target/linux/ar71xx/base-files/lib/ar71xx.sh

@@ -111,6 +111,9 @@ ubnt_unifi_ac_board_detect() {
 	"e517")
 		model="Ubiquiti UniFi-AC-LITE"
 		;;
+	"e527")
+		model="Ubiquiti UniFi-AC-LR"
+		;;
 	"e537")
 		model="Ubiquiti UniFi-AC-PRO"
 		;;

target/linux/ar71xx/image/generic-ubnt.mk

@@ -138,6 +138,12 @@ define Device/ubnt-unifiac-lite
 endef
 TARGET_DEVICES += ubnt-unifiac-lite
 
+define Device/ubnt-unifiac-lr
+  $(Device/ubnt-unifiac-lite)
+  DEVICE_TITLE := Ubiquiti UniFi AC-LR
+endef
+TARGET_DEVICES += ubnt-unifiac-lr
+
 define Device/ubnt-unifiac-mesh
   $(Device/ubnt-unifiac-lite)
   DEVICE_TITLE := Ubiquiti UniFi AC-Mesh