GPU device override is not included in nova helm override by default

[Yang Liu]

Brief Description
-----------------
By default the two supported QAT pci-alias override is included in nova helm system overrides, which enables user to launch VM with QAT VF as is.

However, this override is not done for gpu devices, so user would have to first override the nova helm chart before launching GPU vm.
The GPU user override has to combine the existing user override, so it is fairly tedious to a regular user.

Severity
--------
Minor

Steps to Reproduce
------------------
- system helm-override-show stx-openstack nova openstack

| | pci: |
| | alias: |
| | type: multistring |
| | values: |
| | - '{"vendor_id": "8086", "product_id": "0435", "name": "qat-dh895xcc-pf"}' |
| | - '{"vendor_id": "8086", "product_id": "0443", "name": "qat-dh895xcc-vf"}' |
| | - '{"vendor_id": "8086", "product_id": "37c8", "name": "qat-c62x-pf"}' |
| | - '{"vendor_id": "8086", "product_id": "37c9", "name": "qat-c62x-vf"}' |
| | - '{"name": "gpu"}'

TC-name:

Expected Behavior
------------------
- gpu has similar overrides as qat with supported devices

Actual Behavior
----------------
- gpu override does not have any product_id/vendor_id in nova helm overrides

Reproducibility
---------------
Reproducible

System Configuration
--------------------
All

Branch/Pull Time/Commit
-----------------------
stx master as of 20200525 load

Last Pass
---------
Never

Timestamp/Logs
--------------
Easy to reproduce.

Test Activity
-------------
Regression Testing

[Ghada Khalil (gkhalil)]

This appears to be opened in error. The exact same issue is reported in https://bugs.launchpad.net/starlingx/+bug/1880998