[PATCH] nvmet: Add support for HOST_ID feature.

[Sagi Grimberg]

> The specification says that NVMe-oF must use a 128-bit host ID - from NVMe 1.3, 5.21.1.19.2:
> 
> "The Host Identifier is a mandatory feature in NVMe over Fabrics.  The Host Identifier shall be an extended 128-bit Host Identifier."
> 
> The target should also check the EXHID bit in the Get Features - Host Identifier command.

That's true, We should work with uuid_t for hostids. thanks Daniel.