ASoC: rsnd: don't enable SRC Sync mode when Capture with CMD

It can't use SRC Synchronous convert when Capture if it uses CMD,
because no one provide out side clocks.

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