arm64: dts: imx8mq-mnt-reform2: drop invalid simple-panel compatible

"simple-panel" compatible is not documented and nothing in Linux kernel
binds to it:

  imx8mq-mnt-reform2.dtb: panel: compatible: ['innolux,n125hce-gn1', 'simple-panel'] is too long
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

arch/arm64/boot/dts/freescale/imx8mq-mnt-reform2.dts

@@ -26,7 +26,7 @@ backlight: backlight {
 	};
 
 	panel {
-		compatible = "innolux,n125hce-gn1", "simple-panel";
+		compatible = "innolux,n125hce-gn1";
 		power-supply = <&reg_main_3v3>;
 		backlight = <&backlight>;
 		no-hpd;