net: tls, update curr on splice as well

The curr pointer must also be updated on the splice similar to how
we do this for other copy types.

Fixes: d829e9c ("tls: convert to generic sk_msg interface")
Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Reported-by: Jann Horn <jannh@google.com>
Link: https://lore.kernel.org/r/20231206232706.374377-2-john.fastabend@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Author: jrfastab

net/tls/tls_sw.c

@@ -952,6 +952,8 @@ static int tls_sw_sendmsg_splice(struct sock *sk, struct msghdr *msg,
 		}
 
 		sk_msg_page_add(msg_pl, page, part, off);
+		msg_pl->sg.copybreak = 0;
+		msg_pl->sg.curr = msg_pl->sg.end;
 		sk_mem_charge(sk, part);
 		*copied += part;
 		try_to_copy -= part;