IB/mlx5: Add port protocol stats

Expose new counters using the get protocol stats callback.
We expose the following counters:

|------------------------------------------------------------------------|
|      Name           | IB | EN |           Description                  |
|------------------------------------------------------------------------|
|rx_write_requests    | +  | -  | Number of received WRITE requests for  |
|                     |    |    | the associated QP.                     |
|------------------------------------------------------------------------|
|rx_read_requests     | +  | -  | Number of received READ requests for   |
|                     |    |    | the associated QP.                     |
|------------------------------------------------------------------------|
|rx_atomic_requests   | +  | -  | Number of received ATOMIC requests for |
|                     |    |    | the associated QP.                     |
|------------------------------------------------------------------------|
|out_of_buffer        | +  | +  | Number of drops occurred due to lack   |
|                     |    |    | of WQE for the associated QPs/RQs.     |
|------------------------------------------------------------------------|
|out_of_sequence      | +  | -  | Number of errors in the packet         |
|                     |    |    | transport sequence number              |
|------------------------------------------------------------------------|
|duplicate_request    | +  | +  | Number of received duplicated packets. |
|                     |    |    | A request that previously executed is  |
|                     |    |    | named duplicated.                      |
|------------------------------------------------------------------------|
|rnr_nak_retry_err    | +  | +  | Number of received RNR NAC packets.    |
|                     |    |    | The QP retry limit did not exceed.     |
|------------------------------------------------------------------------|
|packet_seq_err       | +  | +  | Number of received NAK - sequence error|
|                     |    |    | packets. The QP retry limit did not    |
|                     |    |    | exceed.                                |
|------------------------------------------------------------------------|
|implied_nak_err      | +  | +  | Number of times the requester detected |
|                     |    |    | an ACK with a PSN larger than expected |
|                     |    |    | PSN for RDMA READ or ATOMIC response   |
|                     |    |    | The QP retry limit did not exceed.     |
|------------------------------------------------------------------------|
|local_ack_timeout_err| +  | -  | Number of NO ACK responses from        |
|                     |    |    | responder within timer interval.       |
|                     |    |    | The QP retry limit did not exceed.     |
|------------------------------------------------------------------------|

Counters are available if all of them are supported.

Signed-off-by: Mark Bloch <markb@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Reviewed-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>