ipq806x: add support for TP-Link Talon AD7200

ipq806x: add support for TP-Link Talon AD7200

Device hardware: https://deviwiki.com/wiki/TP-LINK_AD7200_(Talon)

The Talon AD7200 is basically an Archer C2600 with a third PCIe lane
and an 802.11ad radio. It looks like the Archers C2600/5400 but the
housing is slightly larger.

Specifications
--------------

  - IPQ8064 dual-core 1400MHz
  - QCA9988 2.4GHz WiFi
  - QCA9990 5GHz WiFi
  - QCA9500 60GHz WiFi
  - 32MB SPI Flash
  - 512MiB RAM
  - 5 GBit Ports (QCA8337)

Installation
------------

Installation is possible from the OEM web interface.
Sysupgrade is possible.
TFTP recovery is possible.
  - Image: AD7200_1.0_tp_recovery.bin

Notes
  - This will be the first 802.11ad device supported by mainline.

Signed-off-by: Gary Cooper <gaco@bitmessage.de>