Add support for driving unselected row/col.

[tzarc]

Description

Slight fix and maintenance burden improvement -- Keychron Q2 uses a pin with a stronger pull resistor than the internal MCU pins, which renders that pin unusable.

Rather than maintaining an entirely separate custom matrix implementation, this allows for driving unselected pins as output-high instead of input-high.

Also removes the broken custom implementation of the Q2 matrix accordingly.

Types of Changes

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

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).

[tzarc]

Renders #16200 irrelevant. Fixes #16097.

[tzarc]

CC @lokher @lalalademaxiya1