CASMPET-6883: remove CPU limit

[bo-quan]

Summary and Scope

Due to the CPU limit set, some customers ran into 503 UAEX errors in a scale environment because OPA could not handle lots of simultaneous requests due to CPU throttling. This PR removes CPU limit for cray-opa to avoid this issue.

Issues and Related PRs

List and characterize relationship to Jira/Github issues and other pull requests. Be sure to list dependencies.

• Resolves CASMPET-6883
• Change will also be needed in <insert branch name here>
• Future work required by [issue id](issue link)
• Documentation changes required in [issue id](issue link)
• Merge with/before/after <insert PR URL here>

Testing

List the environments in which these changes were tested.

Tested on:

• by NERSC

Test description:

How were the changes tested and success verified? If schema changes were part of this change, how were those handled in your upgrade/downgrade testing?

• Were the install/upgrade-based validation checks/tests run (goss tests/install-validation doc)?
• Were continuous integration tests run? If not, why?
• Was upgrade tested? If not, why?
• Was downgrade tested? If not, why?
• Were new tests (or test issues/Jiras) created for this change?

Risks and Mitigations

Low.

Pull Request Checklist

• Version number(s) incremented, if applicable
• Copyrights updated
• License file intact
• Target branch correct
• CHANGELOG.md updated
• Testing is appropriate and complete, if applicable
• HPC Product Announcement prepared, if applicable