Input: exc3000 - split MT event handling from IRQ handler

Input: exc3000 - split MT event handling from IRQ handler

Split out the multitouch event handling into its own function to allow other
events to be handled in the IRQ handler without disturbing the MT handling.
Now that things are separated a bit more, stop treating vendor data requests
special by cehcking for a locked mutex, but just look at the event ID to
figure out if the message is a MT report or a vendor data query reply.

Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Link: https://lore.kernel.org/r/20210125182527.1225245-2-l.stach@pengutronix.de
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>