When a passthru command targets a specific namespace, the ns parameter to
nvme_user_cmd()/nvme_user_cmd64() is set. However, there is currently no
validation that the nsid specified in the passthru command targets the
namespace/nsid represented by the block device that the ioctl was
performed on.

Add a check that validates that the nsid in the passthru command matches
that of the supplied namespace.
Signed-off-by: NNiklas Cassel <niklas.cassel@wdc.com>
Reviewed-by: NJavier González <javier@javigon.com>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Reviewed-by: NKanchan Joshi <joshi.k@samsung.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>