Add PCD statement include files for the PKCS7 test key.
* gEfiSecurityPkgTokenSpaceGuid.PcdPkcs7CertBuffer
* gFmpDevicePkgTokenSpaceGuid.PcdFmpDevicePkcs7CertBufferXdr
These include files can be used in !include statements in PCD
sections of a platform DSC file to assign these PCDs to the
test key certificate values.