ASoC: rsnd: ssi: Check runtime channel number rather than hw_params

The number of channel handled by SSI maybe differs from the one set
in hw_params, currently SSI checks hw_params's channel number,
and constrains to use same channel number, when it is being
used by multiple clients.

This patch corrects to check runtime channel number rather
than channel number set in hw_params.

Signed-off-by: Jiada Wang <jiada_wang@mentor.com>
Signed-off-by: Timo Wischer <twischer@de.adit-jv.com>
[kuninori: adjust to upstreaming]
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>