ch_ktls: do not send snd_una update to TCB in middle

snd_una update should not be done when the same skb is being
sent out.chcr_short_record_handler() sends it again even
though SND_UNA update is already sent for the skb in
chcr_ktls_xmit(), which causes mismatch in un-acked
TCP seq number, later causes problem in sending out
complete record.

Fixes: 429765a1

 ("chcr: handle partial end part of a record")
Signed-off-by: Vinay Kumar Yadav <vinay.yadav@chelsio.com>
Signed-off-by: Rohit Maheshwari <rohitm@chelsio.com>
Signed-off-by: David S. Miller <davem@davemloft.net>