arm64: dts: imx8mn: specify #sound-dai-cells for SAI nodes

arm64: dts: imx8mn: specify #sound-dai-cells for SAI nodes

[ Upstream commit 62fb54148cd6eb456ff031be8fb447c98cf0bd9b ]

Add #sound-dai-cells properties to SAI nodes.

Reviewed-by: Adam Ford <aford173@gmail.com>
Reviewed-by: Fabio Estevam <festevam@gmail.com>
Fixes: 9e9860069725 ("arm64: dts: imx8mn: Add SAI nodes")
Signed-off-by: Marek Vasut <marex@denx.de>
Reviewed-by: Marco Felsch <m.felsch@pengutronix.de>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>