board: add support for chiliBoard

Board support package includes:

 * Buildroot defconfig
 * Mainline Linux kernel v4.9.6
 * Mainline U-Boot (current HEAD revision is used, as board support
   patches are not in stable release yet)
 * genimage config to create sdcard image
 * Board readme.txt

[Peter: use http:// instead of git:// for u-boot]
Signed-off-by: Marcin Niestroj <m.niestroj@grinn-global.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
4 files changed