nvmet: Implement host identifier set feature support

The NVMe specifications mandate support for the host identifier
set_features for controllers that also supports reservations. Satisfy
this requirement by implementing handling of the NVME_FEAT_HOST_ID
feature for the nvme_set_features command. This implementation is for
now effective only for PCI target controllers. For other controller
types, the set features command is failed with a NVME_SC_CMD_SEQ_ERROR
status as before.

As noted in the code, 128 bits host identifiers are supported since the
NVMe base specifications version 2.1 indicate in section 5.1.25.1.28.1
that "The controller may support a 64-bit Host Identifier...".

The RHII (Reservations and Host Identifier Interaction) bit of the
controller attribute (ctratt) field of the identify controller data is
also set to indicate that a host ID of "0" is supported but that the
host ID must be a non-zero value to use reservations.

Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Tested-by: Rick Wertenbroek <rick.wertenbroek@gmail.com>
Tested-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Keith Busch <kbusch@kernel.org>

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