ASoC: audio-graph-card2.c: use of_property_read_u32() for rate

ASoC: audio-graph-card2.c: use of_property_read_u32() for rate

Audio Graph Card2 is using of_get_property(), but it should use
of_property_read_u32() to getting rate. Otherwise the setting will be
strange value. This patch fixup it.

Fixes: 0463aba6ea1dc46 ("ASoC: audio-graph-card2: add Codec2Codec support")
Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Link: https://lore.kernel.org/r/87h741s961.wl-kuninori.morimoto.gx@renesas.com
Signed-off-by: Mark Brown <broonie@kernel.org>