1. Change 0 == Length style to Length == 0

2. Clean BasePeCoff library instance, only keep one copy PeCoffLoaderEx.c file for IA32, X64 and IPF arch
3. Clean the confused comments

git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@5927 6f19259b-4bc3-4df7-8a09-765794883524

MdePkg/Library/BaseMemoryLibRepStr/ScanMem32Wrapper.c

@@ -10,12 +10,14 @@
   THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
   WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
 
-  The following BaseMemoryLib instances share the same version of this file:
+  The following BaseMemoryLib instances contain the same copy of this file:
 
     BaseMemoryLib
     BaseMemoryLibMmx
     BaseMemoryLibSse2
     BaseMemoryLibRepStr
+    BaseMemoryLibOptDxe
+    BaseMemoryLibOptPei
     PeiMemoryLib
     DxeMemoryLib
 
@@ -54,7 +56,7 @@ ScanMem32 (
   IN UINT32      Value
   )
 {
-  if (0 == Length) {
+  if (Length == 0) {
     return NULL;
   }