ASoC: rsnd: ssiu: Support to init different BUSIF instance

Currently ssiu's .init is only called once during audio stream.
But SSIU with different BUSIF, shall be initialized each time,
even they are used in the same audio stream.

This patch introduces ssiu_status for BUSIF0 to BUSIF7 in rsnd_ssiu,
to make sure same .init for different BUSIF can always be executed.

To avoid the first stopped stream to stop the whole SSIU,
which may still has other BUSIF instance running, use usrcnt to count
the usage of SSIU, only the last user of SSIU can stop the whole SSIU.

Signed-off-by: Jiada Wang <jiada_wang@mentor.com>
Signed-off-by: Timo Wischer <twischer@de.adit-jv.com>
[Kuninori: tidyup for upstream]
Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Tested-by: Hiroyuki Yokoyama <hiroyuki.yokoyama.vx@renesas.com>
Signed-off-by: Mark Brown <broonie@kernel.org>