ath79: add support for Extreme Networks WS-AP3805i

ath79: add support for Extreme Networks WS-AP3805i

Specifications:

 - SoC:    Qualcomm Atheros QCA9557-AT4A
 - RAM:	   2x 128MB Nanya NT5TU64M16HG
 - FLASH:  64MB - SPANSION FL512SAIFG1
 - LAN:    Atheros AR8035-A (RGMII GbE with PoE+ IN)
 - WLAN2:  Qualcomm Atheros QCA9557 2x2 2T2R
 - WLAN5:  Qualcomm Atheros QCA9882-BR4A 2x2 2T2R
 - SERIAL: UART pins at J10 (115200 8n1)
           Pinout is 3.3V - GND - TX - RX (Arrow Pad is 3.3V)
 - LEDs: Power (Green/Amber)
   WiFi 5 (Green)
   WiFi 2 (Green)
 - BTN: Reset

Installation:

1. Download the OpenWrt initramfs-image.

Place it into a TFTP server root directory and rename it to 1D01A8C0.img
Configure the TFTP server to listen at 192.168.1.66/24.

2. Connect the TFTP server to the access point.

3. Connect to the serial console of the access point.

Attach power and interrupt the boot procedure when prompted.

Credentials are admin / new2day

4. Configure U-Boot for booting OpenWrt from ram and flash:

 $ setenv boot_openwrt 'setenv bootargs; bootm 0xa1280000'
 $ setenv ramboot_openwrt 'setenv serverip 192.168.1.66;
   tftpboot 0x89000000 1D01A8C0.img; bootm'
 $ setenv bootcmd 'run boot_openwrt'
 $ saveenv

5. Load OpenWrt into memory:

 $ run ramboot_openwrt

6. Transfer the OpenWrt sysupgrade image to the device.

Write the image to flash using sysupgrade:

 $ sysupgrade -n /path/to/openwrt-sysupgrade.bin

Signed-off-by: Albin Hellström <albin.hellstrom@gmail.com>
[rename vendor - minor style fixes - update commit message]
Signed-off-by: David Bauer <mail@david-bauer.net>