Fix the LCD library's handling of errors.

[WillNilges]

Doesn't seem to be compatible with anyhow, so I can't use the ? syntactic sugar.

 the trait bound `hd44780_driver::error::Error: std::error::Error` is not satisfied
    the following other types implement trait `FromResidual<R>`:
      <Result<T, F> as FromResidual<Yeet<E>>>
      <Result<T, F> as FromResidual<Result<Infallible, E>>>
    required for `anyhow::Error` to implement `From<hd44780_driver::error::Error>`
    required for `Result<(), anyhow::Error>` to implement `FromResidual<Result<Infallible, hd44780_driver::error::Error>>` [E0277]