(2) Remove unused library class EdkPeCoffLoaderX64Lib and library instance EdkPeCoffLoaderX64Lib, because current BasePeCoffLib can supports IA32, EBC,
& X64 images all.
git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@2069 6f19259b-4bc3-4df7-8a09-765794883524