video: test: Support checking copy frame buffer contents

video: test: Support checking copy frame buffer contents

The video tests have a helper function to generate a pseudo-digest of
frame buffer contents, but it only does so for the main one. There is
another check that the copy frame buffer is the same as that. But
neither is enough to test if only the modified regions are copied to the
copy frame buffer, since we will want the two to be different in very
specific ways.

Add a boolean argument to the existing helper function to indicate which
frame buffer we want to inspect, and update the existing callers.

Signed-off-by: Alper Nebi Yasak <alpernebiyasak@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Link: https://lore.kernel.org/u-boot/20230821135111.3558478-3-alpernebiyasak@gmail.com/