nvmet: use macro definition for setting nmic value

This makes the code more readable.
Signed-off-by: Max Gurtovoy <mgurtovoy@nvidia.com>
Reviewed-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

drivers/nvme/target/admin-cmd.c

@@ -541,7 +541,7 @@ static void nvmet_execute_identify_ns(struct nvmet_req *req)
 	 * Our namespace might always be shared.  Not just with other
 	 * controllers, but also with any other user of the block device.
 	 */
-	id->nmic = (1 << 0);
+	id->nmic = NVME_NS_NMIC_SHARED;
 	id->anagrpid = cpu_to_le32(req->ns->anagrpid);
 
 	memcpy(&id->nguid, &req->ns->nguid, sizeof(id->nguid));