video: Allow a copy framebuffer with pre-allocated fb

At present it is not possible for the video driver to use a pre-allocated
frame buffer (such as is done with EFI) with the copy framebuffer. This
can be useful to speed up the display.

Adjust the implementation so that copy_size can be set to the required
size, with this being allocated if the normal framebuffer size is 0.

Signed-off-by: Simon Glass <sjg@chromium.org>
2 files changed