This patch adds CTU (Channel Transfer Unit) support for rsnd driver.
But, it does nothing to data at this point, but is required for MIX
support.

CTU design is a little different from other IPs (CTU0 is including
CTU00 - CTU03, and CTU1 is including CTU10 - CTU13, these have different
register mapping) We need to care about it on this driver.
Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Tested-by: Keita Kobayashi <keita.kobayashi.ym@renesas.com>
Signed-off-by: Mark Brown <broonie@kernel.org>