2api: Remove UI callback functions

With a series of UI callback functions removed from depthcharge (see the
long CL list in Cq-Depend below), now we can remove them from vboot2

TEST=make runtests -j
TEST=emerge-corsola libpayload depthcharge

Cq-Depend: chromium:3581323, chromium:3581320, chromium:3587669
Cq-Depend: chromium:3611670, chromium:3631467, chromium:3631405
Cq-Depend: chromium:3677727, chromium:3681952
Change-Id: Icccaf81b8a6f16780bf68a6f1f3aa01689fc9ed8
Signed-off-by: Yu-Ping Wu <yupingso@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/vboot_reference/+/3682754
Reviewed-by: Hsuan Ting Chen <roccochen@chromium.org>
6 files changed