touchdriver: Port atmel-mxt driver from rocko
The old driver supports the tuning and update tooling. Changes in contrast to the rocko version:
- Add fallthrough macro where needed
- Move content of dt-bindings/input/atmel_mxt_ts.h (kernel 4.1.15) to atmel_mxt.h because the file content in version 5.15 is different.
BCS 746-000997