mpc85xx: add support for Enterasys WS-AP3715i

mpc85xx: add support for Enterasys WS-AP3715i

Hardware
--------

SoC:   NXP P1010 (1x e500 @ 800MHz)
RAM:   256M DDR3 (2x Samsung K4B1G1646G-BCH9)
FLASH: 32M NOR (Spansion S25FL256S)
BTN:   1x Reset
WiFi:  1x Atheros AR9590 2.4 bgn 3x3
       2x Atheros AR9590 5.0 an 3x3
ETH:   2x Gigabit Ethernet (Atheros AR8033 / AR8035)
UART:  115200 8N1 (RJ-45 Cisco)

Installation
------------
1. Grab the OpenWrt initramfs, rename it to ap3715.bin. Place it in
   the root directory of a TFTP server and serve it at
   192.168.1.66/24.

2. Connect to the serial port and boot the AP. Stop autoboot in U-Boot
   by pressing Enter when prompted. Credentials are identical to the one
   in the APs interface. By default it is admin / new2day.

3. Alter the bootcmd in U-Boot:

 $ setenv ramboot_openwrt "setenv ipaddr 192.168.1.1;
   setenv serverip 192.168.1.66; tftpboot 0x2000000 ap3715.bin; bootm"

 $ setenv boot_openwrt "sf probe 0; sf read 0x2000000 0x140000 0x1000000;
   bootm 0x2000000"

 $ setenv bootcmd "run boot_openwrt"

 $ saveenv

4. Boot the initramfs image

 $ run ramboot_openwrt

5. Transfer the OpenWrt sysupgrade image to the AP using SCP. Install
   using sysupgrade.

 $ sysupgrade -n <path-to-sysupgrade.bin>

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