Add missing QT_NO_CAST_FROM_ASCII

Add missing QT_NO_CAST_FROM_ASCII

to QLatin1String's compare operators that takes const char *s or QByteArray.
Such comparison leads to a potential misuse since QByteArray could contain any arbitrary data
in any arbitrary encoding and QLatin1String is used to only contain strings in UTF-8 -
they are just a different beasts aimed for different purposes, and since QT_NO_CAST_*_ASCII
disallow indirect conversions and require the user to know what he's doing,
let's be consistent here too.

Change-Id: I9bf5f326495157db8a6af064d6154961b7861a7e
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>