nvme: Check for Security send/recv support before issuing commands.

We need to verify that the controller supports the security
commands before actually trying to issue them.

Signed-off-by: Scott Bauer <scott.bauer@intel.com>
[hch: moved the check so that we don't call into the OPAL code if not
      supported]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
diff --git a/drivers/nvme/host/nvme.h b/drivers/nvme/host/nvme.h
index fd94c94..b097722 100644
--- a/drivers/nvme/host/nvme.h
+++ b/drivers/nvme/host/nvme.h
@@ -140,6 +140,7 @@ struct nvme_ctrl {
 	u32 max_hw_sectors;
 	u16 oncs;
 	u16 vid;
+	u16 oacs;
 	atomic_t abort_limit;
 	u8 event_limit;
 	u8 vwc;