Fix RESET not working for keyboards with Kiibohd bootloader

[Andrew-Fahmy]

This is a fix for #6112. Keyboards with the Kiibohd bootloader would go into secure DFU mode. In secure DFU mode the bootloader would do an extra key verification where it would look for a key in the first block of the new firmware. There is a way to disable this functionality, and after talking with @haata, I was able to implement this fix.

I have a K-type and this fixed the issue on my keyboard. If anyone that has a different keyboard, let me know if this fix also works on your board.

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

• Fixes WhiteFox - RESET goes to "Kiibohd DFU Secure", cannot flash - needs to enter "Kiibohd DFU" #6112

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]

If I understand this correctly, the change can be simplified as the current code is already modifying the VBAT register.

[Andrew-Fahmy]

That's definitely a cleaner way of doing it, thanks for the suggestion!