[U-Boot] Panda revision detection

[Peter Robinson]

Hi All,

There's some logic in board/ti/panda/panda.c to detect the various
panda revisions (es/a4) and set the board/board_name variables but, at
least on 2015.04/07, it doesn't appear to work so on an ES board the
board_name is still just panda and fence findfdt doesn't set the
correct dtb details. I had a quick poke at it around the edges to see
if I can work out what went wrong but I didn't get far, can someone
with some more understanding of it take a look?

Peter