vboot/ui: Always show page up/down buttons in log screen

Always show page up/down buttons in log screen.
Beep if users select the page up button on the first page or the page
down button on the last page.

BRANCH=puff, zork
BUG=b:146399181, b:163301076
TEST=emerge-puff depthcharge
TEST=emerge-zork depthcharge
TEST=navigate to the debug info screen by <TAB>

Cq-Depend: chromium:2361582
Signed-off-by: Hsuan Ting Chen <roccochen@chromium.org>
Change-Id: I29a567554f9283ea3fca0f58fb31c7056523c2a9
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/vboot_reference/+/2361823
Commit-Queue: Hung-Te Lin <hungte@chromium.org>
Reviewed-by: Yu-Ping Wu <yupingso@chromium.org>
2 files changed