UefiCpuPkg/RegisterCpuFeaturesLib: Fix ECC issues.

Changes include:
1. Remove extra white space at the end of line.
2. Add comments for the new add function parameter.
3. Update IN OUT tag for function parameter.

Cc: Dandan Bi <dandan.bi@intel.com>
Cc: Ruiyu Ni <ruiyu.ni@intel.com>
Cc: Laszlo Ersek <lersek@redhat.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Eric Dong <eric.dong@intel.com>
Reviewed-by: Ruiyu Ni <ruiyu.ni@intel.com>

UefiCpuPkg/Library/RegisterCpuFeaturesLib/PeiRegisterCpuFeaturesLib.c

@@ -146,6 +146,8 @@ GetProcessorInformation (
 
   @param[in]  Procedure               A pointer to the function to be run on
                                       enabled APs of the system.
+  @param[in]  MpEvent                 The Event used to sync the result.
+
 **/
 VOID
 StartupAPsWorker (