video: Skip bitmaps which do not fit into the screen in cfb_console

The cfb console driver is trying to prevent bitmaps to spill over the
screen, but the calculations assume that at least part of the bitmap
fits into the screen area. In reality there could be bitmap elements
which are completely out of the screen area, they just need to be
discarded.

Signed-off-by: Vadim Bendebury <vbendeb@chromium.org>
Signed-off-by: Simon Glass <sjg@chromium.org>