qualcommax: ipq60xx: add support for Cambium Networks XE3-4

qualcommax: ipq60xx: add support for Cambium Networks XE3-4

Cambium Networks XE3-4 is a tri-radio Wi-Fi 6/6E 4×4/2×2 AP.

Hardware:
    Model:    Cambium Networks XE3-4
    CPU:      IPQ6010/AP-CP01-C3, SoC Version: 1.0 @ 800 MHz
    Memory:   1 GiB
    Flash:    512 MiB Macronix MX30UF2G18AC + W25Q128FW
    Ethernet: 1x 1 GbE   (QCA8072)
              1x 2.5 GbE (QCA8081)
    Buttons:  1x Reset
    Serial:   TX, RX, GND
    Baudrate: 115200
    Radios:   Qualcomm Atheros IPQ6018 802.11ax - 2x2 - 2GHz
              Qualcomm Atheros IPQ6018 802.11ax - 2x2 - 5GHz
              Qualcomm Atheros QCN9074 802.11ax - 4x4 - 5GHz or 6GHz
              BLE 4.1
    Power:    32.0W 802.3bt5 PoE++
              25.5W 802.3at with USB, BT disabled
    Size:     215mm x 215mm
    Ports:    1x USB 2.0
    Antenna:  6 GHz: 6.29 dBi, Omni    30 dBm
              5 GHz: 6.12 dBi, Omni    31 dBm
              2.4 GHz: 4.85 dBi, Omni  29 dBm
    LEDs:     Multi-color status LEDs
    Mounting: Wall, ceiling or T-bar

Installation: Serial connection
1. Open the AP to get access to the board. Connect RX, TX and GND.
2. Power on the AP, and short the CS pin of the SPI flash with
   one of the APs GND pins.
3. Transfer the initramfs image with TFTP
   (Default server IP is 192.168.0.120)
   # tftpboot factory.ubi
4. Flash the rootfs partition
   # flash rootfs
5. Reboot the AP
   # reset

Signed-off-by: Kristian Skramstad <kristian+github@83.no>
Link: https://github.com/openwrt/openwrt/pull/15633
Signed-off-by: Robert Marko <robimarko@gmail.com>