qga: Introduce disk smart

After assigning a NVMe/SCSI controller to guest by VFIO, we lose
everything on the host side. A guest uses these devices exclusively,
we usually don't care the actions on these devices. But there is a
low probability that hitting physical hardware warning, we need a
chance to get the basic smart log info.

Introduce disk smart, and implement NVMe smart on linux.

Thanks to Keith and Marc-André.

CC: Keith Busch <kbusch@kernel.org>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: zhenwei pi <pizhenwei@bytedance.com>
Message-Id: <20220420022610.418052-3-pizhenwei@bytedance.com>