mediatek: filogic: add support for WAVLINK WL-WN573HX3

The WL-WN573HX3 is an AX3000 outdoor Access Point by WAVLINK,
also sold in Europe as 7Links WLR-1300 (ZX-5612).

Specifications:

- MT7981B + MT7976 AX3000 2x2 DBDC (160 MHz)
- 16 MiB SPI NOR, 256 MiB RAM
- Gigabit ethernet port, 802.3af PoE
- IP67 outdoor case for wall or pole mounting with
    four single band RP-SMA fiberglass antennas (8 dBi)

Installation:

- OEM Web UI is at 192.168.30.1 which will forward to
    http://netlogin.link (using a captive portal)
- login with default password `admin`
- skip setup wizard by navigating directly to
    http://netlogin.link/html/meshUpgrade.html
- upload WN573HX3-sysupgrade.bin
- reset to factory defaults to discard OEM UCI settings

MAC address assignment:

LAN         80:xx:xx:76:xx:25  hw 0x44e
WLAN 2.4G   80:xx:xx:76:xx:27  factory 0x04 (label MAC)
WLAN 5G	    82:xx:xx:46:xx:27
pair key    8a:xx:xx:76:xx:27  also on label, not used by OpenWrt

Signed-off-by: Sebastian Schaper <openwrt@sebastianschaper.net>

target/linux/mediatek/image/filogic.mk

@@ -1678,6 +1678,24 @@ define Device/wavlink_wl-wn586x3
 endef
 TARGET_DEVICES += wavlink_wl-wn586x3
 
+define Device/wavlink_wl-wn573hx3
+  DEVICE_VENDOR := WAVLINK
+  DEVICE_MODEL := WL-WN573HX3
+  DEVICE_ALT0_VENDOR := 7Links
+  DEVICE_ALT0_MODEL := WLR-1300
+  DEVICE_DTS := mt7981b-wavlink-wl-wn573hx3
+  DEVICE_DTS_DIR := ../dts
+  DEVICE_DTS_LOADADDR := 0x47000000
+  IMAGE_SIZE := 14336k
+  KERNEL := kernel-bin | lzma | \
+	fit lzma $$(KDIR)/image-$$(firstword $$(DEVICE_DTS)).dtb
+  DEVICE_PACKAGES := kmod-mt7915e kmod-mt7981-firmware mt7981-wo-firmware
+  SUPPORTED_DEVICES += mediatek,mt7981-spim-nor-rfb
+  IMAGES = WN573HX3-sysupgrade.bin
+  IMAGE/WN573HX3-sysupgrade.bin := append-kernel | pad-to 128k | append-rootfs | pad-rootfs | check-size | append-metadata
+endef
+TARGET_DEVICES += wavlink_wl-wn573hx3
+
 define Device/xiaomi_mi-router-ax3000t
   DEVICE_VENDOR := Xiaomi
   DEVICE_MODEL := Mi Router AX3000T