tree: Add NVM subsystem controller identifier

tree: Add NVM subsystem controller identifier

This commit introduces a field "cntlid" for controller,
that contains the NVM subsystem unique identifier assigned
to each controller device in an NVM subsystem.

While attaching a namespace, typically user needs to specify the
controller identifier (cntlid). The cntlid could be referenced from
sysfs (/sys/class/nvme/nvmeX/cntlid) but it would be nice to have
a direct option.

Signed-off-by: Nilay Shroff <nilay@linux.ibm.com>
Link: https://lore.kernel.org/r/20240326065752.164286-1-nilay@linux.ibm.com
Signed-off-by: Daniel Wagner <dwagner@suse.de>