arm64: dts: meson-g12a: Add CMA reserved memory

In order to handle Video Output and later on Video decoding,
add a reserved CMA pool with a similar 256MiB size as other SoCs.
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: Kevin Hilman <khilman@baylibre.com>

arch/arm64/boot/dts/amlogic/meson-g12a.dtsi

@@ -79,6 +79,14 @@ secmon_reserved: secmon@5000000 {
 			reg = <0x0 0x05000000 0x0 0x300000>;
 			no-map;
 		};
+
+		linux,cma {
+			compatible = "shared-dma-pool";
+			reusable;
+			size = <0x0 0x10000000>;
+			alignment = <0x0 0x400000>;
+			linux,cma-default;
+		};
 	};
 
 	sm: secure-monitor {