hw/arm: add very initial support for Canon DIGIC SoC

hw/arm: add very initial support for Canon DIGIC SoC

DIGIC is Canon Inc.'s name for a family of SoC
for digital cameras and camcorders.

There is no publicly available specification for
DIGIC chips. All information about DIGIC chip
internals is based on reverse engineering efforts
made by CHDK (http://chdk.wikia.com) and
Magic Lantern (http://www.magiclantern.fm) projects
contributors.

Signed-off-by: Antony Pavlov <antonynpavlov@gmail.com>
Reviewed-by: Andreas Färber <afaerber@suse.de>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Peter Crosthwaite <peter.crosthwaite@xilinx.com>
Message-id: 1387188908-754-2-git-send-email-antonynpavlov@gmail.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>