Bluetooth: hidp: don't send boot-protocol messages as HID-reports

If a device is registered as HID device, it is always in Report-Mode.
Therefore, we must not send Boot-Protocol messages on
hidinput_input_event() callbacks. This confuses devices and may cause
disconnects on protocol errors.

We disable the hidinput_input_event() callback for now. We can implement
it properly later, but lets first fix the current code by disabling it.

Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
Acked-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>