This allows our EFI API to create a device path node for NVMe
devices.  It adds the necessary device path struct, uses the
nvme namespace accessor to retrieve the id and eui64, and also
provides support for the device path text protocol.
Signed-off-by: NPatrick Wildt <patrick@blueri.se>
Tested-by: NHeinrich Schuchardt <xypron.glpk@gmx.de>
Reviewed-by: NHeinrich Schuchardt <xypron.glpk@gmx.de>