ASoC: rsnd: rsnd_get_dalign() needs to care SSIU, not SSI

SSIU was controlled by SSI before, but
commit c7f69ab5("ASoC: rsnd: use mod base common method on SSIU")
separated it into ssiu.c

But, it didn't care about rsnd_get_dalign() for judging SSI_BUSIF_DALIGN
register value which changes the stream data order.
This function will be called from cmd/src/ssiu now, but current code
still cares ssi, not ssiu.
This patch fix it up

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>