arm64: dts: imx8qxp: Add audio SAI nodes

This adds the sai nodes attached to aips1 bus. These can be shared with
imx8qm as well. Input clock from ACM is always feed to mclk1 only. Others
are unused and are connected to a dummy clock.

Signed-off-by: Alexander Stein <alexander.stein@ew.tq-group.com>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>