ch_ktls: don't free skb before sending FIN

If its a last packet and fin is set. Make sure FIN is informed
to HW before skb gets freed.

Fixes: 429765a1

 ("chcr: handle partial end part of a record")
Signed-off-by: Rohit Maheshwari <rohitm@chelsio.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>