ASoC: rsnd: avoid pointless loop in rsnd_mod_interrupt()

Current Renesas sound driver doesn't have 1:1 relationship between
stream <-> mod because it is supporting MIX. Because of this reason
rsnd_mod_interrupt() is searching correspond mod by for loop.
But this loop is not needed, because each mod has own type.
This patch avoid pointless loop by using mod->type.

This patch is good for SSI-parent support, because stream might have
2 SSI as SSI-parent/child. SSI interrupt handler will be called twice
if stream has SSI-parent without this patch.

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