Fix the issue that GCC treat enum type as unsigned int which incompatible with UEFI spec's INT32. 
Fix the issue that GCC treat enum type as unsigned int which incompatible with UEFI spec's INT32. 

git-svn-id: 5648d1bec6962b0a6d1d1b40eba8cf5cdb62da3d@10347 6f19259b-4bc3-4df7-8a09-765794883524

MattDevo/edk2,MattDevo/edk2,MattDevo/edk2,MattDevo/edk2,MattDevo/edk2,MattDevo/edk2,MattDevo/edk2,MattDevo/edk2