vboot: reshuffle legacy UI files

- Use "vboot_ui_legacy" prefix for all legacy UI-related files.

- Merge vboot_display.{c,h} and vboot_ui_legacy_common.c into
  vboot_ui_legacy.{c,h}.

- Move VbDisplayScreen and VbDisplayMenu implementation into
  their respective vboot_ui_legacy_*.c files.

- Update VbCheckDisplayKey to take |screen| argument to avoid
  reading disp_current_screen global variable.

BUG=b:124141368, chromium:968464
TEST=make clean && make runtests
BRANCH=none

Change-Id: I777551e4968ca22282901d22a262a8f2ec849702
Signed-off-by: Joel Kitching <kitching@google.com>
Cq-Depend: chromium:2214615
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/vboot_reference/+/2112322
Tested-by: Joel Kitching <kitching@chromium.org>
Commit-Queue: Joel Kitching <kitching@chromium.org>
Reviewed-by: Joel Kitching <kitching@chromium.org>
16 files changed