ASoC: rsnd: amend .probe/.remove call for DPCM

commit 1a5658c2 ("ASoC: rsnd: count .probe/.remove for
rsnd_mod_call()") solved multi-resource-free issue, by putting
.probe/.remove under count control. But,it breaks sound mixing case
(if it was used under DPCM). In such case, it uses MIXn/DVCn/SSIn,
and these should be always probed.
This patch reverted above patch, and solved the same issue by
modifing _rsnd_kctrl_remove() function.

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Mark Brown <broonie@kernel.org>