ARM: dts: TS-4800: add basic device tree

This device tree adds support for TS-4800 by Technologic Systems. This
board is based on MX51-babbage, but there are some subtle differences in
the pins used, and there is an additional FPGA that is memory-mapped.

More details here:
  http://wiki.embeddedarm.com/wiki/TS-4800



Signed-off-by: Damien Riegel <damien.riegel@savoirfairelinux.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>