tls: rx: assume crypto always calls our callback

[ Upstream commit 1c699ffa ]

If crypto didn't always invoke our callback for async
we'd not be clearing skb->sk and would crash in the
skb core when freeing it. This if must be dead code.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Stable-dep-of: f7fa16d4 ("tls: decrement decrypt_pending if no async completion will be called")
Signed-off-by: Sasha Levin <sashal@kernel.org>