At the last step of PE image authentication, an image's hash value must be
compared with a message digest stored as the content (of SpcPeImageData type)
of pkcs7's contentInfo.
Fixes: commit 4540dabdcaca ("efi_loader: image_loader: support image authentication")
Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>