Fix RGBW not turning off when saturation is set to `0`.

[bryan065]

(Temporary?) Fix for RGBW not turning off when saturation is set to 0.

Description

Using RGB_MATRIX and RGBW LED's, when any LED's are set to 0 saturation, they won't turn off when toggled/timeout/sleep.

Warning: My white LED shines much brighter now when set to 0 saturation and true white (instead of RGB array white), this resulted in my keyboard pulling about 30% more power when the full keyboard LEDs are set to white. Had to turn down maximum brightness accordingly (which would also limit your RGB LED brightness). Future PR for separate RGB maximum brightness and W maximum brightness perhaps?

Code credited to @drashna .

Types of Changes

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

Issues Fixed or Closed by This PR

• n/a

Checklist

• [x] My code follows the code style of this project: C, Python
• [x] 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.
• [x] I have read the CONTRIBUTING document.
• [ ] I have added tests to cover my changes.
• [x] I have tested the changes and verified that they work and don't break anything (as well as I can manage).