HID: multitouch: add MT_QUIRK_IGNORE_DUPLICATES

This quirk allows a device to reuse a contact id when sending garbage
inactive contacts at the end of a report.

Signed-off-by: Benjamin Tissoires <benjamin.tissoires@gmail.com>
Reviewed-by: Henrik Rydberg <rydberg@euromail.se>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>