vboot: Remove VbExKeyboard* functions from vboot API

Since the UI code has been moved to depthcharge, VbExKeyboardRead and
VbExKeyboardReadWithFlags are not used in any function in vboot now.

Remove these two functions in vboot.

TEST=DEBUG=1 make -j test_setup && make -j runtests

Cq-Depend: chromium:3142696
Signed-off-by: edisonhello <edisonhello@google.com>
Change-Id: I6ce983bf400141681dfd33a0e3c30fe74a992c77
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/vboot_reference/+/3143812
Reviewed-by: Yu-Ping Wu <yupingso@chromium.org>
2 files changed