Fixed signed/unsigned and unused parameter warnings

[SRGDamia1]

Thank you for creating a pull request to contribute to Adafruit's GitHub code! Before you open the request please review the following guidelines and tips to help it be more easily integrated:

• Describe the scope of your change--i.e. what the change does and what parts of the code were modified. This will help us understand any risks of integrating the code.

No functional changes - only a cast to remove warnings about comparisons between signed and unsigned integers and commenting out an unused parameter to suppress that warning.

• Describe any known limitations with your change. For example if the change doesn't apply to a supported platform of the library please mention it.

No known limitations

• Please run any tests or examples that can exercise your modified code. We strive to not break users of the code and running tests/examples helps with this process.

No functionality of the code was changed