Fix joystick initialization

[zvecr]

Description

Extracted from #22947 to make DD changes cleaner/clearer.

• output_pin/ground_pin removed
  • Previously planned removal never happened
  • users will now need to override weak init/sample functions
• Correctly inits joystick_axes to virtual when no config
  • input_pin would equal zero which is a valid value on chibios platforms (eg rp2040)
• Correct handling of input_pin as 0xFF is not a valid value to use
  • again could be a valid value on chibios platforms
• Fixes compilation when JOYSTICK_AXIS_COUNT == 0

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).