Handle return type of EVP_MD_size

Handle return type of EVP_MD_size

Return type is int, but we often use it in contexts
where we expect size_t. So just cast it. Nothing else
to do really.

Change-Id: I22b93c807f1be99fab450708f686fce4aa6d5cef
Signed-off-by: Frank Lichtenheld <frank@lichtenheld.com>
Acked-by: Gert Doering <gert@greenie.muc.de>
Gerrit URL: https://gerrit.openvpn.net/c/openvpn/+/1133
Message-Id: <20250922204059.23226-1-gert@greenie.muc.de>
URL: https://sourceforge.net/p/openvpn/mailman/message/59237213/
Signed-off-by: Gert Doering <gert@greenie.muc.de>