U-Boot for the Bachmann electronic GmbH OT1200 devices

There are two different versions of the base board, which differ
in the way ethernet is done. The variant detection is done during
runtime based on the address of the found phy.

- "mr" variant
FEC is connected directly to an ethernet switch (KSZ8895). The ethernet
port is always up and auto-negotiation is not possible.

- normal variant
FEC is connected to a normal phy and auto-negotiation is possible.

The variant name is part of the dtb file name loaded by u-boot. This
make is possible to boot the linux kernel and make use variant specific
devicetree (fixed-phy link).

In order to support different display resoltuions/sizes the OT1200 devices
are making use of EDID data stored in an i2c EEPROM.