board/boundarydevices: rework and update u-boot scripts

Those scripts are executed by u-boot in order to detect the hardware
configuration (board, displays etc...), configure the bootargs and
device tree accordingly or update the bootloader located in NOR flash.

This update is necessary due to the kernel bump to version 3.10.53.

The rework consists of replacing the binaries by their text file
equivalent and generate the binaries from the post-build.sh script.

Signed-off-by: Gary Bisson <gary.bisson@boundarydevices.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>