vboot/ui: remove validate_selection function

Given that we are sending the full vb2_ui_context into
UI-related functions, it's impossible to fully validate that
called functions don't modify UI state in unexpected ways.

Assume UI-related functions are mutating vb2_ui_context data
correctly.  Screen init functions (see CL:2168072) will be
used to set selected_item and disabled_mask before displaying
a screen for the first time.

change_screen() is also changed to return a vb2_error_t value
to be more consistent with action functions.

BUG=b:146399181
TEST=make clean && make runtests
BRANCH=none

Change-Id: Icda68f95a835b9143b8dd085d8dbdb7bced04775
Signed-off-by: Joel Kitching <kitching@google.com>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/vboot_reference/+/2182084
Tested-by: Joel Kitching <kitching@chromium.org>
Commit-Queue: Yu-Ping Wu <yupingso@chromium.org>
Reviewed-by: Joel Kitching <kitching@chromium.org>
Reviewed-by: Yu-Ping Wu <yupingso@chromium.org>
3 files changed