ALSA: dummy: Add customizable volume min/max.

Add module parameters to support customized min/max volume leveling,
which will be useful to test devices with different volume granularity.

Signed-off-by: YJ Lee <yunjunlee@chromium.org>
Link: https://lore.kernel.org/r/20220912072945.760949-1-yunjunlee@chromium.org


Signed-off-by: Takashi Iwai <tiwai@suse.de>