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

Fixes: d829e9c4 ("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.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>