BaseTools/GenPage: Fix potential memory leak

Cc: Liming Gao <liming.gao@intel.com>
Cc: Yonghong Zhu <yonghong.zhu@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Hao Wu <hao.a.wu@intel.com>
Reviewed-by: Liming Gao <liming.gao@intel.com>

BaseTools/Source/C/GenPage/GenPage.c

@@ -431,9 +431,11 @@ main (
   //
   result = GenBinPage (BaseMemory, InputFile, OutputFile);
   if (result < 0) {
+    free (BaseMemory);
     return STATUS_ERROR;
   }
 
+  free (BaseMemory);
   return 0;
 }