console->scroll_up() was hanging when console->rows is 0. This
was happening on delan if no screen was attached. If there are no
rows, just return.
BUG=b:119234919
TEST=Boot delan with no flat panel. System boots to OS
Change-Id: Ib022d3c6fc0c9cf360809dca28761a50c787304a
Signed-off-by: Martin Roth <martinroth@chromium.org>
Reviewed-on: https://review.coreboot.org/c/30092
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Raul Rangel <rrangel@chromium.org>