MdePkg FirmwareManagement.h: Fix code style issue

MdePkg FirmwareManagement.h: Fix code style issue

Cc: Michael D Kinney <michael.d.kinney@intel.com>
Cc: Liming Gao <liming.gao@intel.com>
Cc: Dandan Bi <dandan.bi@intel.com>
Cc: Hess Chen <hesheng.chen@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Star Zeng <star.zeng@intel.com>
Reviewed-by: Michael D Kinney <michael.d.kinney@intel.com>
Reviewed-by: Dandan Bi <dandan.bi@intel.com>