1. Add a support for <Word>.<Word> format of PCD offset.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Hess Chen <hesheng.chen@intel.com>
Reviewed-by: Liu, Yingke D <yingke.d.liu@intel.com> 
Reviewed-by: Feng, Bob C <bob.c.feng@intel.com>


git-svn-id: https://svn.code.sf.net/p/edk2-buildtools/code/trunk/BaseTools@2663 c2973edb-eda0-4c78-bc6a-9341b269661f