dm: video: test: Add tests for the video uclass

Add tests that check that the video console is working correcty. Also check
that text output produces the expected result. Test coverage includes
character output, wrapping and scrolling.

Signed-off-by: Simon Glass <sjg@chromium.org>
Acked-by: Anatolij Gustschin <agust@denx.de>
5 files changed