Ensure that rgb+via compiles in all cases

[drashna]

Description

Needs defines from rgb engines to work. Added default/placeholders.

Ran multibuild to ensure all of the keymaps compile.

Types of Changes

• Core
• Bugfix

Checklist

• My code follows the code style of this project: C, Python
• I have read the PR Checklist document and have made the appropriate changes.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• I have tested the changes and verified that they work and don't break anything (as well as I can manage).

[daskygit]

Maybe these defaults should be set regardless of if VIA is enabled or not?

[drashna]

Maybe these defaults should be set regardless of if VIA is enabled or not?

They are. These preprocessors are pulled from rgblight.h and rgb_matrix.c respectively.