The command "system device-image-apply" won't be successful if the label is not passed

[Venkata Veldanda]

Brief Description
-----------------
In StarlingX FPGA user guide
https://docs.starlingx.io/node_management/starlingx-kubernetes/hardware_acceleration_devices/updating-an-intel-n3000-fpga-image.html

3. Apply the device image on one or all supported devices.

The description says that "Apply a device image to all supported devices:"

~(keystone_admin)$ system device-image-apply <image_uuid>

But the API gets rejected if the label (<key1>=<value1>) is not specified

Severity
--------
Minor

Steps to Reproduce
------------------
Per the guide https://docs.starlingx.io/node_management/starlingx-kubernetes/hardware_acceleration_devices/updating-an-intel-n3000-fpga-image.html

The above command doesn't return any error or success

<Reproducible/Intermittent/Seen once>
Reproducible

System Configuration
--------------------
Simplex(AIO)

Timestamp/Logs
--------------

bash.log - command execution
2021-01-27T19:56:13.000 controller-0 -sh: info HISTORY: PID=1380366 UID=42425 system device-image-apply d31086d2-f7d6-4129-8421-a0d298fa21f1

Corresponding sys-inv.log
sysinv 2021-01-27 19:56:14.783 87255 INFO sysinv.api.controllers.v1.device_image [-] No host device labels specified

Test Activity
-------------
Evaluation

Either the doc or the sw should be fixed.

[Ghada Khalil (gkhalil)]

screening: assigning to Teresa to triage. This is likely a doc issue since FPGA image update testing is successful in windriver.