Input: simplify event handling logic

Input: simplify event handling logic

Streamline event handling code by providing batch implementations for
filtering and event processing and using them in place of the main
event handler, as needed, instead of having complex branching logic
in the middle of the event processing code.

Reviewed-by: Jeff LaBundy <jeff@labundy.com>
Reviewed-by: Benjamin Tissoires <bentiss@kernel.org>
Link: https://lore.kernel.org/r/20240703213756.3375978-5-dmitry.torokhov@gmail.com
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>