arm64: dts: imx8mn: remove "simple-bus" for anatop

Remove "simple-bus" compatible for device anatop,
since no child nodes exist under it and it is not
a populated bus.
Signed-off-by: Fancy Fang <chen.fang@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

arch/arm64/boot/dts/freescale/imx8mn.dtsi

@@ -349,7 +349,7 @@ cpu_speed_grade: speed-grade@10 {
 
 			anatop: anatop@30360000 {
 				compatible = "fsl,imx8mn-anatop", "fsl,imx8mm-anatop",
-					     "syscon", "simple-bus";
+					     "syscon";
 				reg = <0x30360000 0x10000>;
 			};