Add quirk to reset channel on sample end

Resetting channels on sample end doesn't allow sample retrig after
the end of a single-shot sample. See hi-hats in channel 3 of Guardian
Dragon. On the other hand, IT wants the channel to be reset (see the
it_sample_porta.it test module), so add a quirk for that.

Signed-off-by: Claudio Matsuoka <cmatsuoka@gmail.com>
[test] Use common mixer data comparator

Signed-off-by: Claudio Matsuoka <cmatsuoka@gmail.com>
Update changelog

Signed-off-by: Claudio Matsuoka <cmatsuoka@gmail.com>