Change stream_buf_read_setup_dowork parameter to struct steam_buf

Change stream_buf_read_setup_dowork parameter to struct steam_buf

This methods only ever access sock->stream_buf so make the method
simpler by just having a parameter sb.

Change-Id: I3deb7cd75db3cb280fa8d9c637cd3bde3881d6e3
Signed-off-by: Arne Schwabe <arne-openvpn@rfc2549.org>
Acked-by: Frank Lichtenheld <frank@lichtenheld.com>
Gerrit URL: https://gerrit.openvpn.net/c/openvpn/+/1483
Message-Id: <20260211150747.113906-1-frank@lichtenheld.com>
URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg35595.html
Signed-off-by: Gert Doering <gert@greenie.muc.de>
(cherry picked from commit 6ac80e99092feb31223507a9f5b32c296125b86b)