HID: add driver for ELO 4000/4500

This is a driver for ELO 4000/4500 devices which report themselves as
HID devices, but do not really send HID events on touch. So we
introduce a new HID 'quirk' driver with a raw_event handler where we
take care of those events.

What we need additionally is an input_configured hook, because the
device does not mention anything about PRESSURE and TOUCH in its
report descriptor, but it actually generate those. So we set the bits
in the corresponding input_dev in that hook.

Thanks to Petr Ostadal who was willing to test the driver. The rest of
Cc's listed below had something to do with that driver over the years
in our enterprise tree.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Tested-by: Petr Ostadal <postadal@suse.cz>
Cc: Oliver Neukum <oliver@neukum.org>
Cc: Vojtech Pavlik <vojtech@suse.cz>
Cc: Egbert Eich <eich@suse.com>
Cc: Libor Pechacek <lpechacek@suse.cz>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>