1. add some comments to clarify AsciiStrDecimalToUintn() can help filtering un-decimal characters.
2. change the condition judgment to “Index < 15” rather than (Index + 1 ) <16.
git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@9803 6f19259b-4bc3-4df7-8a09-765794883524