Deprecate QFont::setRawName() and QFont::rawName()

We don't support xlfd fonts anymore and indeed QFont::setRawName()
is an empty method.

[Changelog][QtGui] QFont::setRawName() and QFont::rawName() are
deprecated.

Change-Id: Ic52d42a9bc200ba8b246dd4e28c77f84e086dad5
Reviewed-by: Tor Arne Vestbø <tor.arne.vestbo@digia.com>
Reviewed-by: Konstantin Ritt <ritt.ks@gmail.com>
Reviewed-by: Simon Hausmann <simon.hausmann@digia.com>
Reviewed-by: Eskil Abrahamsen Blomfeldt <eskil.abrahamsen-blomfeldt@digia.com>