libcr51sign: import from gBMC

Validate the cr51 descriptor of the BIOS image. It can also
parse the BIOS version and write it to a file.

Signed-off-by: Nan Zhou <nanzhoumails@gmail.com>
Change-Id: I098be66b228da6f3514d3f13166a1bb4e1e718fb
13 files changed