When a driver also uses a same name, there will be a link error: one or more multiply defined symbols found. Use a specific name for mSmst to avoid the link error. Cc: Jiewen Yao <jiewen.yao@intel.com> Contributed-under: TianoCore Contribution Agreement 1.0 Signed-off-by: Star Zeng <star.zeng@intel.com> Reviewed-by: Jiewen Yao <jiewen.yao@intel.com>