Input: i8042 - Add support for platform filter contexts

Input: i8042 - Add support for platform filter contexts

Currently the platform filter cannot access any driver-specific state
which forces drivers installing a i8042 filter to have at least some
kind of global pointer for their filter.

Allow callers of i8042_install_filter() to submit a context pointer
which is then passed to the i8042 filter. This frees drivers from the
responsibility of having to manage this global pointer themself.

Also introduce a separate type for the i8042 filter (i8042_filter_t)
so that the function definitions can stay compact.

Tested on a Dell Inspiron 3505.

Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Armin Wolf <W_Armin@gmx.de>
Link: https://lore.kernel.org/r/20250113221314.435812-1-W_Armin@gmx.de
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>