MFC r349969

bhyve: Create EUI64 for NVMe namespaces

Accept an IEEE Extended Unique Identifier (EUI-64) from the command
line for each NVMe namespace. If one isn't provided, it will create one
based on the CRC16 of:

• the FreeBSD IEEE OUI
• PCI bus, device/slot, function values
• Namespace ID

Approved by: imp (mentor)