ASoC: rsnd: core.c: add WARN_ON() on rsnd_channel_normalization()

chan > 8 or chan < 0 shouldn't happen.
This patch uses WARN_ON() for such case.

Reported-by: Pavel Machek <pavel@denx.de>
Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Link: https://lore.kernel.org/r/87y2x530a4.wl-kuninori.morimoto.gx@renesas.com


Signed-off-by: Mark Brown <broonie@kernel.org>