ar71xx: add support for UniFi-AC-Mesh-Pro

This adds the build option for UniFi AC Mesh Pro as well as
model detection for it.
The device is a hardware clone of the AC Pro.

- SoC: QCA9563-AL3A (775Mhz)
- RAM: 128MiB
- Flash: 16MiB - dual firmware partitions!
- LAN: 2x 1000M - POE+
- Wireless:
        2.4G: QCA9563
          5G: UniFi Chip, QCA988X compatible

Signed-off-by: Christoph Krapp <achterin@googlemail.com>
(cherry picked from commit 987b961537)

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

@@ -98,22 +98,28 @@ ubnt_xm_board_detect() {
 	[ -z "$model" ] || AR71XX_MODEL="${model}${magic:3:1}"
 }
 
-ubnt_ac_lite_get_mtd_part_magic() {
+ubnt_unifi_ac_get_mtd_part_magic() {
 	ar71xx_get_mtd_offset_size_format EEPROM 12 2 %02x
 }
 
-ubnt_ac_lite_board_detect() {
+ubnt_unifi_ac_board_detect() {
 	local model
 	local magic
 
-	magic="$(ubnt_ac_lite_get_mtd_part_magic)"
+	magic="$(ubnt_unifi_ac_get_mtd_part_magic)"
 	case ${magic:0:4} in
 	"e517")
 		model="Ubiquiti UniFi-AC-LITE"
 		;;
+	"e537")
+		model="Ubiquiti UniFi-AC-PRO"
+		;;
 	"e557")
 		model="Ubiquiti UniFi-AC-MESH"
 		;;
+	"e567")
+		model="Ubiquiti UniFi-AC-MESH-PRO"
+		;;
 	esac
 
 	[ -z "$model" ] || AR71XX_MODEL="${model}"
@@ -1369,10 +1375,11 @@ ar71xx_board_detect() {
 		;;
 	*"UniFi-AC-LITE/MESH")
 		name="unifiac-lite"
-		ubnt_ac_lite_board_detect
+		ubnt_unifi_ac_board_detect
 		;;
-	*"UniFi-AC-PRO")
+	*"UniFi-AC-PRO/MESH-PRO")
 		name="unifiac-pro"
+		ubnt_unifi_ac_board_detect
 		;;
 	*"UniFiAP Outdoor")
 		name="unifi-outdoor"