vboot: remove some vboot1 SharedData-related functions

Remove VbSharedDataInit, VbSharedDataReserve,
VbSharedDataSetKernelKey, along with their corresponding tests.

In tests/verify_kernel and utility/load_kernel_test, just copy the
kernel subkey manually for now, until we update LoadKernel to
retrieve the key from vboot2 workbuf instead.

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

Change-Id: I7055be10f0d7a38502fd8108f0bc93c5b78f06c9
Signed-off-by: Joel Kitching <kitching@google.com>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/vboot_reference/+/1844598
Reviewed-by: Joel Kitching <kitching@chromium.org>
Commit-Queue: Joel Kitching <kitching@chromium.org>
Tested-by: Joel Kitching <kitching@chromium.org>
16 files changed