arm64: dts: imx8mq: Use 'dsi' as node name

Use 'dsi' as node name to avoid the following schema warning:

imx8mq-evk.dtb: mipi-dsi@30a00000: $nodename:0: 'mipi-dsi@30a00000' does not match '^dsi(@.*)?$'
From schema: Documentation/devicetree/bindings/display/bridge/nwl-dsi.yaml
Signed-off-by: Fabio Estevam <festevam@denx.de>
Acked-by: Alexander Stein <alexander.stein@ew.tq-group.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

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

@@ -1056,7 +1056,7 @@ sec_jr2: jr@3000 {
 				};
 			};
 
-			mipi_dsi: mipi-dsi@30a00000 {
+			mipi_dsi: dsi@30a00000 {
 				compatible = "fsl,imx8mq-nwl-dsi";
 				reg = <0x30a00000 0x300>;
 				clocks = <&clk IMX8MQ_CLK_DSI_CORE>,