Cleanup Juno r2 code to build with -DENABLE_WARNINGS=ON

[tpatki]

Description

Addresses several -Werror=format and -Werror=unused-variable` on Juno r2, but doesn't fix #526 yet.

Fixes #527.

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature/architecture support (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation update
• Build/CI update

How Has This Been Tested?

• Juno r2

Checklist:

• I have run ./scripts/check-code-format.sh and confirm my code code follows the style guidelines of variorum
• I have added comments in my code
• My changes generate no new warnings (build with -DENABLE_WARNINGS=ON)
• New and existing unit tests pass with my changes