arm64: dts: meson-g12b-odroid-n2: add missing amlogic, s922x compatible

This fixes the following DT schemas check errors:
meson-g12b-odroid-n2.dt.yaml: /: compatible: ['hardkernel,odroid-n2', 'amlogic,g12b'] is not valid under any of the given schemas
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Reviewed-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Kevin Hilman <khilman@baylibre.com>

arch/arm64/boot/dts/amlogic/meson-g12b-odroid-n2.dts

@@ -12,7 +12,7 @@
 #include <dt-bindings/sound/meson-g12a-tohdmitx.h>
 
 / {
-	compatible = "hardkernel,odroid-n2", "amlogic,g12b";
+	compatible = "hardkernel,odroid-n2", "amlogic,s922x", "amlogic,g12b";
 	model = "Hardkernel ODROID-N2";
 
 	aliases {