dco_win: In dco_new_key, document size assumptions for the integer casts

dco_win: In dco_new_key, document size assumptions for the integer casts

And make all casts explicit so that compiler doesn't complain.

Change-Id: I612bf3b1c56d70a89fc04fad6fe36fd9fadfd258
Signed-off-by: Frank Lichtenheld <frank@lichtenheld.com>
Acked-by: MaxF <max@max-fillinger.net>
Gerrit URL: https://gerrit.openvpn.net/c/openvpn/+/1221
Message-Id: <20250926165151.1502-1-gert@greenie.muc.de>
URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg33229.html
Signed-off-by: Gert Doering <gert@greenie.muc.de>