nvme: add tracing of zns commands

When support for the NVMe ZNS commands was merged, tracing of these has
been omitted.

Add nvme_cmd_zone_mgmt_send, nvme_cmd_zone_mgmt_recv as well as
nvme_cmd_zone_append to the nvme driver's tracing facility.

Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>