initramfs-test-image: add kmscube if OpenGL is enabled
initramfs-test-image: add kmscube if OpenGL is enabled

Add a simple tool usefull for testing the OpenGL support, kmscube.

Signed-off-by: Dmitry Baryshkov <2dcd7ecf02101ef1dca344c0511f3ffb180907c2@linaro.org>

ndechesne/meta-qcom,ndechesne/meta-qcom,ndechesne/meta-qcom