IS31FL3737 Global Current Setting

[Electro707]

Description

This tiny PR adds the ability to define a global current setting for the IS31FL3737 Driver which supports it. Currently it is hardcoded to 0xFF

Types of Changes

• Core
• Bugfix
• New feature
• Enhancement/optimization
• Keyboard (addition or update)
• Keymap/layout/userspace (addition or update)
• Documentation

Issues Fixed or Closed by This PR

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).

[drashna]

It looks like there are a good number of other controllers that also support this. it would likely be a good idea to add support to them, as well.

[Electro707]

Should I make those changes as part of this PR or create another one? Imo i think it would be best to have it as part of this PR and expand the scope of it to adding the global current control setting to all other ISSI controllers).

[drashna]

For now, this is fine, but a separate PR with the additional changes would be nice!