CodeReview for MdePkg/BaseMemoryXXX libraries. Refine file description, function comments and move some redundant logic.

git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@6167 6f19259b-4bc3-4df7-8a09-765794883524

MdePkg/Library/BaseMemoryLibOptPei/MemLibInternals.h

@@ -145,7 +145,9 @@ InternalMemZeroMem (
   @param  Length            Length of DestinationBuffer and SourceBuffer memory
                             regions to compare. Must be non-zero.
 
-  @retval 0     if MemOne == MemTwo
+  @return 0                 All Length bytes of the two buffers are identical.
+  @retval Non-zero          The first mismatched byte in SourceBuffer subtracted from the first
+                            mismatched byte in DestinationBuffer.
 
 **/
 INTN

MdePkg/Library/BaseMemoryLibOptPei/ZeroMemWrapper.c

@@ -50,9 +50,6 @@ ZeroMem (
 {
   ASSERT (!(Buffer == NULL && Length > 0));
   ASSERT (Length <= (MAX_ADDRESS - (UINTN)Buffer + 1));
-  if (Length == 0) {
-  	return Buffer;
-  }  
   
   return InternalMemZeroMem (Buffer, Length);
 }