efi_loader: tcg2 protocol updates

On pull reuqest
https://lists.denx.de/pipermail/u-boot/2020-November/432735.html


V4 of the patchset was sent instead of the v5.
This is the v4->v5 missing diff

Signed-off-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>