nvme: Stop probing a removed device

There is no reason the nvme controller can ever return all 1's from
reading the CSTS register. This patch returns an error if we observe
that status. Without this, we may incorrectly proceed with controller
initialization and unnecessarilly rely on error handling to clean this.

Signed-off-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: Jens Axboe <axboe@fb.com>