arm64: dts: meson-gx: drop the vpu dmc memory cell

This fixes the following DT schemas check errors:
meson-gxl-s805x-libretech-ac.dt.yaml: vpu@d0100000: reg-names: Additional items are not allowed ('dmc' was unexpected)
meson-gxl-s805x-libretech-ac.dt.yaml: vpu@d0100000: reg-names: ['vpu', 'hhi', 'dmc'] is too long

The 'dmc' register area was replaced by the amlogic,canvas property
which was introduced in commit f1726043 ("arm64: dts: meson-gx:
add dmcbus and canvas nodes.") and commit cf342879 ("arm64: dts:
meson-gx: Add canvas provider node to the vpu")
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-gx.dtsi

@@ -544,9 +544,8 @@ sd_emmc_c: mmc@74000 {
 		vpu: vpu@d0100000 {
 			compatible = "amlogic,meson-gx-vpu";
 			reg = <0x0 0xd0100000 0x0 0x100000>,
-			      <0x0 0xc883c000 0x0 0x1000>,
-			      <0x0 0xc8838000 0x0 0x1000>;
-			reg-names = "vpu", "hhi", "dmc";
+			      <0x0 0xc883c000 0x0 0x1000>;
+			reg-names = "vpu", "hhi";
 			interrupts = <GIC_SPI 3 IRQ_TYPE_EDGE_RISING>;
 			#address-cells = <1>;
 			#size-cells = <0>;