Define BBUI_IMAGE_WHITE_PATTERN variable to indicate which image is
allowed to be displayed in image combobox.
Define BBUI_IMAGE_BLACK_PATTERN variable to indicate which image is NOT
allowed to be displayed in image combobox.
This fixes [YOCTO #1581]
(Bitbake rev: 960461bc12945675af3081eb469f932f4a6eb1cd)
Signed-off-by: Dongxiao Xu <dongxiao.xu@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>