Fix DxeCapsuleLib build failure

Signed-off-by : Chao Zhang <chao.b.zhang@intel.com>
Reviewed-by   : Gao Liming <liming.gao@intel.com>

git-svn-id: svn://svn.code.sf.net/p/edk2/code/trunk/edk2/IntelFrameworkModulePkg@14779 6f19259b-4bc3-4df7-8a09-765794883524