cxgbe: Make the TOE TLS stats per-queue instead of per-port.

[jhb]

Summary

This avoids some atomics by using counter_u64 for TX and relying on
existing single-threading (single ithread per rxq) for RX.

[jhb]

sys/dev/cxgbe/t4_sge.c

1252

A question here is if we want to have alloc_ofld_txq and free_ofld_txq helper functions in t4_sge.c as we currently have for offload RX queues. If so, I would probably go back and do that in the previous commit that introduced struct sge_ofld_txq

[jhb]

• Update for alloc/free_txq_ofld().