Originally, there are following implementation:

1) The collect action of platform's dynamic PCD database is trigged by module's autogen action. 
2) If platform is used for more than one architecture, two platform object will be created

Above two rules will cause an issue for single module building that if
1) platform support IA32 and X64
2) do single module for X64 module

then, the dynamic PCD for IA32 modules will missed in PCD database, because no IA32 module need autogen so collection action for IA32 module is not trigged.

Now, I think the collection action for platform dynamic PCD should be explicitly called after PlatformAutoGen is created.

git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@8323 6f19259b-4bc3-4df7-8a09-765794883524