options: Review use of positive_atoi vs atoi_constrained

options: Review use of positive_atoi vs atoi_constrained

Replace where it is useful.

While here also add a missing cast in atoi_constrained.

Change-Id: Id440917f433aab1a7db608ba04fa95ba47c2ddde
Signed-off-by: Frank Lichtenheld <frank@lichtenheld.com>
Acked-by: Gert Doering <gert@greenie.muc.de>
Gerrit URL: https://gerrit.openvpn.net/c/openvpn/+/1153
Message-Id: <20251009205951.32301-1-gert@greenie.muc.de>
URL: https://sourceforge.net/p/openvpn/mailman/message/59244617/
Signed-off-by: Gert Doering <gert@greenie.muc.de>