Fixed problem with sign extension in print lib. PrintXY could not print out French characters like é. 
Fixed problem with sign extension in print lib. PrintXY could not print out French characters like é. 

git-svn-id: 5648d1bec6962b0a6d1d1b40eba8cf5cdb62da3d@3761 6f19259b-4bc3-4df7-8a09-765794883524

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