example: fix mi identify failed with error cntid

This command failed when we try to identify a controller that the
controller id is 1.

Refer to the `Figure 273: Identify - CNS Values`:
+-----------+-------+
| CNS Value | CNTID |
+-----------+-------+
| 01h       | N     |
+-----------+-------+
When CNS is 01h, the CNTID field is ignored.

See `Figure 270: Identify - Command Dword 10`:
If this field is not used as part of the Identify operation, then
* host software shall clear this field to 0h for backwards compatibility
(0h is a valid controller identifier);
* and the controller shall ignore this field.

This filed is set to controller id in the example code, but it should be
0 when CNS is 1.

PS: The NVMe that we are testing does not ignore the CNTID field and
returns an error when the CNTID field is not 0.

Signed-off-by: Jian Zhang <zhangjian.3032@bytedance.com>

examples/mi-mctp.c

@@ -201,7 +201,7 @@ int do_identify(nvme_mi_ep_t ep, int argc, char **argv)
 
 	partial = argc > 2 && !strcmp(argv[2], "--partial");
 
-	ctrl = nvme_mi_init_ctrl(ep, tmp);
+	ctrl = nvme_mi_init_ctrl(ep, ctrl_id);
 	if (!ctrl) {
 		warn("can't create controller");
 		return -1;
@@ -211,7 +211,7 @@ int do_identify(nvme_mi_ep_t ep, int argc, char **argv)
 	id_args.args_size = sizeof(id_args);
 	id_args.cns = NVME_IDENTIFY_CNS_CTRL;
 	id_args.nsid = NVME_NSID_NONE;
-	id_args.cntid = ctrl_id;
+	id_args.cntid = 0;
 	id_args.csi = NVME_CSI_NVM;
 
 	/* for this example code, we can either do a full or partial identify;