Input: atmel_mxt_ts - print all instances when dumping objects

For objects with multiple instances, dump them all, prepending each with
its "Instance #".

[rydberg@euromail.se: break out mxt_show_instance()]
Signed-off-by: Daniel Kurtz <djkurtz@chromium.org>
Signed-off-by: Henrik Rydberg <rydberg@euromail.se>