HID: hid-multitouch: change default mt_class

The safest quirk for a device (the one that works out of the box for
most of them) is MT_QUIRK_NOT_SEEN_MEANS_UP. Indeed, it does not
make any assumption on the device. When adding a new device, we can
easily test it against MT_CLS_DEFAULT, and then optimize it with other
quirks: that's why no device use MT_CLS_DEFAULT right now.

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