Ktls: never skip stamping tags for NIC TLS

The newer RACK and BBR TCP stacks have added a mechanism
to disable hardware packet pacing for TCP retransmits.
This mechanism works by skipping the send-tag stamp
on rate-limited connections when the TCP stack calls
ip_output() with the IP_NO_SND_TAG_RL flag set.

When doing NIC TLS, we must ignore this flag, as
NIC TLS packets must always be stamped. Failure
to stamp a NIC TLS packet will result in crypto
issues.

Reviewed by: hselasky, rrs
Sponsored by: Netflix, Mellanox