ArmPkg/SemiHostingSerialPortLib: Return number of written bytes in SerialPortWrite()

It was previously returning '0' written bytes that was interprating by the higher
layers as a failing operation.

Fix proposed by Eugene Cohen (HP)



git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@12026 6f19259b-4bc3-4df7-8a09-765794883524

ArmPkg/Library/SemiHostingSerialPortLib/SerialPortLib.c

@@ -98,7 +98,7 @@ SerialPortWrite (
       SemihostWriteString ((CHAR8 *) PrintBuffer);
   }
 
-  return 0;
+  return NumberOfBytes;
 }