update the error message for the case of the HII PCD VariableOffset exceed the maximum value of 0xFFFF. 
Signed-off-by: Feng, Bob C <bob.c.feng@intel.com>
Reviewed-by: Hess Chen <hesheng.chen@intel.com>
Reviewed-by: Liu, Yingke D <yingke.d.liu@intel.com> 
Reviewed-by: Boyer, Donna J <donna.j.boyer@intel.com>


git-svn-id: https://svn.code.sf.net/p/edk2-buildtools/code/trunk/BaseTools@2632 c2973edb-eda0-4c78-bc6a-9341b269661f