Fix LocateDevicePath() to return proper error status code. It was returning EFI_INVA...

Fix LocateDevicePath() to return proper error status code.  It was returning EFI_INVALID_PARAMETER if Device was NULL even if not handles matched the search criteria.  The proper behavior is to return EFI_NOT_FOUND if not handles match the search criteria, and only return EFI_INVALID_PARAMETER if at least one match is found and Device is NULL.

Also update function header comment block for LocateDevicePath() to match UEFI Specification.

git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@11406 6f19259b-4bc3-4df7-8a09-765794883524