1. Add Doxygen comments for FRAMEWORK_EFI_PEI_SERVICES;
2. Remove definition of EFI_PEI_STARTUP_DESCRIPTOR. It is not defined in the PEI CIS spec and is implementation specific.
git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@8730 6f19259b-4bc3-4df7-8a09-765794883524