vboot: check for recovery mode with VB2_CONTEXT_RECOVERY_MODE

When the specific recovery reason is not needed, just use
(ctx->flags & VB2_CONTEXT_RECOVERY_MODE) to determine whether
or not we are in recovery mode.

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

Change-Id: I37f1bc066d970a51dfd7ef38cba519c00e1e764f
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/vboot_reference/+/2053252
Commit-Queue: Joel Kitching <kitching@chromium.org>
Tested-by: Joel Kitching <kitching@chromium.org>
Reviewed-by: Julius Werner <jwerner@chromium.org>
4 files changed