hw/nvme: add Identify Endurance Group List

hw/nvme: add Identify Endurance Group List

Commit 73064edfb864 ("hw/nvme: flexible data placement emulation")
intorudced NVMe FDP feature to nvme-subsys and nvme-ctrl with a
single endurance group #1 supported.  This means that controller should
return proper identify data to host with Identify Endurance Group List
(CNS 19h).  But, yes, only just for the endurance group #1.  This patch
allows host applications to ask for which endurance group is available
and utilize FDP through that endurance group.

Reviewed-by: Klaus Jensen <k.jensen@samsung.com>
Signed-off-by: Minwoo Im <minwoo.im@samsung.com>
Signed-off-by: Klaus Jensen <k.jensen@samsung.com>