BBB u-boot

[Chris Johns]

Hi,

I built u-boot from the git master repo for the Beaglebone Black and I have been
working with an RTEMS u-boot type image plus a local patch to by pass
`bsp_fdt_copy` that is now called for this board. With the change there is a
crash as `r3` is not valid with the RTEMS OS entry.

I have also tested a Linux image format and the kernel crashes early in
`bsp_start_hook_1`. This is with the same patch to by pass `bsp_fdt_copy`.

What configuration was used to test the GSoC code?

The change to add `bsp_fdt_copy` has created an inconsistency because u-boot
master has support for RTEMS images which uses the RTEMS OS boot entry and the
parameters used for that call are different to the ARM specific Linux entry
parameters. It is sensible for someone, me in this case, to use an RTEMS image
on RTEMS however this hidden dependence on a Linux type image makes using RTEMS
difficult. I am ok with having the upstream u-boot RTEMS OS support removed
however we need to have a working BBB before this can happen.

I have created https://devel.rtems.org/ticket/3152 to track the issue.

Chris