PerformancePkg/Dp_App: Fix a memory leak issue in Dp.

The allocated memory of ParamPackage is not freed.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Cinnamon Shia <cinnamon.shia@hpe.com>
Reviewed-by: Qiu Shumin <shumin.qiu@intel.com>
Reviewed-by: Star Zeng <star.zeng@intel.com>

PerformancePkg/Dp_App/Dp.c

@@ -526,6 +526,9 @@ Done:
   SafeFreePool (StringPtr);
   SafeFreePool (mPrintTokenBuffer);
 
+  if (ParamPackage != NULL) {
+    ShellCommandLineFreeVarList (ParamPackage);
+  }
   if (CustomCumulativeData != NULL) {
     SafeFreePool (CustomCumulativeData->Name);
   }