arm64: dts: imx8mq: fix SAI compatible

The i.MX8M SAI block is not compatible with the i.MX6SX one, as the
register layout has changed due to two version registers being added
at the beginning of the address map. Remove the bogus compatible.

Fixes: 8c61538d ("arm64: dts: imx8mq: Add SAI2 node")
Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Reviewed-by: Daniel Baluta <daniel.baluta@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

arch/arm64/boot/dts/freescale/imx8mq.dtsi

@@ -715,8 +715,7 @@ uart2: serial@30890000 {
 
 			sai2: sai@308b0000 {
 				#sound-dai-cells = <0>;
-				compatible = "fsl,imx8mq-sai",
-					     "fsl,imx6sx-sai";
+				compatible = "fsl,imx8mq-sai";
 				reg = <0x308b0000 0x10000>;
 				interrupts = <GIC_SPI 96 IRQ_TYPE_LEVEL_HIGH>;
 				clocks = <&clk IMX8MQ_CLK_SAI2_IPG>,