Modify autogen code for DynamicEx type PCD.

Modify autogen code for DynamicEx type PCD.
1) Roll back PcdSetEx/PcdGetEx macro, module developer must input the token space guid explicitly, because in a module maybe two PCD with same CName and token number but in different token space guid.
2) Modify the generated value for _PCD_MODE_xxx for DynamicEx PCD. This macro will be mapped to PcdLibSetEx/PcdLibGetEx directly, and the parameter of token space guid is auto generated.
3) For token space guid array variable autogened, only one copy will be exists in a module's autogen C file for different PCD which are in same token space guid.

git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@575 6f19259b-4bc3-4df7-8a09-765794883524