ath79: add support for Siemens WS-AP3610

ath79: add support for Siemens WS-AP3610

Hardware
--------
SoC:  Atheros AR7161
RAM:  Samsung K4H511638D-UCCC
      2x 64M DDR1
SPI:  Micron M25P128 (16M)
WiFi: Atheros AR9160 bgn
      Atheros AR9160 an
ETH:  Broadcom BCM5481
LED:  Power (Green/Red)
      ETH (Green / Blue / Yellow)
          (PHY-controlled)
      WiFi 5 (Green / Blue)
      WiFi 2 (Green / Blue)
BTN:  Reset

Serial: Cisco-Style RJ45 - 115200 8N1

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

1. Download the OpenWrt initramfs-image. Place it into a TFTP server
   root directory and rename it to 1401A8C0.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 (bootdelay is 1 second).

4. Configure the U-Boot environment for booting OpenWrt from Ram and
   flash:

   $ setenv boot_openwrt 'setenv bootargs; bootm 0xbf080000'
   $ setenv ramboot_openwrt 'setenv serverip 192.168.1.66;
     tftpboot; bootm'
   $ saveenv

5. Load OpenWrt into memory:

   $ run ramboot_openwrt

   Wait for the image to boot.

6. Transfer the OpenWrt sysupgrade image to the device. Write the image
   to flash using sysupgrade:

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

Signed-off-by: David Bauer <mail@david-bauer.net>