ferris/0_1: update I2C API usage

[fauxpark]

Description

These I2C_READ and I2C_WRITE defines don't need to exist.

The custom matrix code for ferris/0_1 has been updated to align more closely with 0_2 by using i2c_read/write_register() instead. This was actually already done for 0_2 in #21273, but not 0_1 for some reason. They could possibly be completely identical but I mainly just wanted to clean up the i2c_master header.

Types of Changes

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