ASoC: pcm3168a: ignore 0 Hz settings

Some sound card try to set 0 Hz as reset, but it is impossible.
This patch ignores it to avoid error return.

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Link: https://lore.kernel.org/r/87a6yjy5sy.wl-kuninori.morimoto.gx@renesas.com


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