ASoC: rsnd: fixup mod ID for CTU regmap read/write

commit c16015f3 ("ASoC: rsnd: add .get_id/.get_id_sub")
add new .get_id/.get_id_sub to indicate module ID/subID.
It is used for SSIU and CTU. In SSIU case, subID indicates BUSIF,
but register settings is based on SSIU ID.
OTOH, in CTU case, subID indicates CTU channel, and register settings
is based on it. This means regmap read/write function needs to care it.
This patch fixup this issue. It can't play MIXed sound without this
patch.

Fixes: c16015f3

 ("ASoC: rsnd: add .get_id/.get_id_sub")
Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Mark Brown <broonie@kernel.org>