tls_crypt: Avoid some conversion warnings

tls_crypt: Avoid some conversion warnings

The casts should be safe, since one is a constant
(but got type from sizeof()) and the other is
limited by the buffer length.

While here make the code in tls_crypt_v2_wrap_client_key
as little easier to follow.

Change-Id: I3f11423834814bab5d653f160fc2326dae4c0e8e
Signed-off-by: Frank Lichtenheld <frank@lichtenheld.com>
Acked-by: Gert Doering <gert@greenie.muc.de>
Gerrit URL: https://gerrit.openvpn.net/c/openvpn/+/1379
Message-Id: <20251116140754.17177-1-gert@greenie.muc.de>
URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg34466.html
Signed-off-by: Gert Doering <gert@greenie.muc.de>