lantiq: add support for AVM FRITZ!Box 7412

lantiq: add support for AVM FRITZ!Box 7412

Hardware:

SoC: Lantiq VRX 220
CPU Cores: 2x MIPS 34Kc at 500 MHz
RAM: 128 MiB 250 MHz
Storage: 128 MiB NAND flash
Ethernet: built-in Fast Ethernet switch, only port 2 is used
Wireless: Atheros AR9287-BL1A b/g/n with 2 pcb antennas
Modem: built-in A/VDSL2 modem
DECT: Dialog SC14441
LEDs: 1 two-color, 4 one-color
Buttons: 2
FXS: 1 port via TAE or RJ12 connector
Everything except FXS/DECT works
(no drivers for AVM's FXS implementation with SC14441).

Installation:

Use the eva_ramboot.py script to load an initramfs image on the
device. Run it a few seconds after turning the device on.
$ scripts/flashing eva_ramboot 192.168.178.1 bin/targets/lantiq/xrx200/openwrt-lantiq-xrx200-avm_fritz7412-initramfs-kernel.bin
If it fails to find the device try the ip address 169.254.120.1.
(Firmware updates or the recovery tool apparently change it.)

IMPORTANT: set lzma compression in ramdisk options, bootloader stalls
when receiving uncompressed images.

The device will load it in ram and boot it. You can reach it under
the openwrt default ip address 192.168.1.1.

Check if the key linux_fs_start is not set to 1 in tffs:
$ fritz_tffs_nand -d /dev/mtd1 -n linux_fs_start
If it is set to 1, the bootloader will select the wrong set of
partitions. Restart the box and install an FritzOS upgrade or do a
recovery. Afterwards start again at step 1.

Run sysupgrade to persistently install OpenWRT.

Signed-off-by: Valentin Spreckels <Valentin.Spreckels@Informatik.Uni-Oldenburg.de>
Signed-off-by: Andy Binder <AndyBinder@gmx.de>