VbDisplayDebugInfo: Don't redraw screen
VbDisplayDebugInfo: Don't redraw screen

VbDisplayDebugInfo() currently redraws the screen before displaying
debug info for no apparent reason. This should generally not be
necessary because the debug output doesn't tend to change, so redrawing
it over old debug output works fine on its own. Removing this gets rid
of an unnecessary flicker.

BRANCH=None
BUG=None
TEST=Hit Tab a few times on Kevin, flicker is less noticable.

Change-Id: I1e82ece1d25274461fa306c0ab821251a90a2692
Signed-off-by: Julius Werner <4d12f06cff3725783b352157673a720bc67c4afe@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/1548302
Reviewed-by: Furquan Shaikh <6be5c96c464778f89679b1062a2e0a6af93d2aa5@chromium.org>

coreboot/vboot,coreboot/vboot,coreboot/vboot,coreboot/vboot,coreboot/vboot