Enable g_is31_leds PROGMEM for RGB Matrix IS31FL3737 driver

[ccullin]

Description

Moves the RGB Matrix g_is31_leds led config array to PROGMEM when using the issi/IS31FL3737 driver.
This array uses ~3bytes per rgb led and this change frees up considerable SRAM for the average rgb matrix keyboard.
Implementing this change to other issi drivers is trivial

This is a Break Change.

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

#13443
*

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).

[fauxpark]

Any boards using the 3737 will need to be updated in this PR.

[ccullin]

Any boards using the 3737 will need to be updated in this PR.

agreed. a #define flag coukd be added to make configurable but this adds complexity.

[drashna]

Looks like the mt84, and planck/ez are the only boards in repo that use this controller

[ccullin]

Looks like the mt84, and planck/ez are the only boards in repo that use this controller

@drashna @fauxpark - I am reading the comment as I need to update the mentioned keyboard files. Please let me know if this is not required and I will blackout them out. (new commit coming).

[drashna]

Awesome, thanks!

And verified working on my planck EZ Glow.