ARM: sun6i: Add Colombus board defconfig

The Colombus board is an A31 evaluation board from WITS Technology.

Maxime has kindly agreed to maintain this board.

[1] http://lists.denx.de/pipermail/u-boot/2014-September/190043.html



Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Cc: Maxime Ripard <maxime.ripard@free-electrons.com>
Acked-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Acked-by: Ian Campbell <ijc@hellion.org.uk>