ARM: dts: aspeed: Enable the GFX IP

The GFX controller is the internal graphics device used by the SoC
(opposed to the one connected via the PCIe device and used by the host).

This configures it with a framebuffer region and adds it to the command
line so kernel boot messages appear on the display.

Enabled for Romulus, Witherspoon, and the ASPEED AST2500 EVB.
Reviewed-by: Andrew Jeffery <andrew@aj.id.au>
Signed-off-by: Joel Stanley <joel@jms.id.au>

arch/arm/boot/dts/aspeed-ast2500-evb.dts

@@ -13,12 +13,25 @@ aliases {
 
 	chosen {
 		stdout-path = &uart5;
-		bootargs = "console=ttyS4,115200 earlyprintk";
+		bootargs = "console=tty0 console=ttyS4,115200 earlyprintk";
 	};
 
 	memory@80000000 {
 		reg = <0x80000000 0x20000000>;
 	};
+
+	reserved-memory {
+		#address-cells = <1>;
+		#size-cells = <1>;
+		ranges;
+
+		gfx_memory: framebuffer {
+			size = <0x01000000>;
+			alignment = <0x01000000>;
+			compatible = "shared-dma-pool";
+			reusable;
+		};
+	};
 };
 
 &fmc {
@@ -98,3 +111,8 @@ &ehci1 {
 &uhci {
 	status = "okay";
 };
+
+&gfx {
+     status = "okay";
+     memory-region = <&gfx_memory>;
+};

arch/arm/boot/dts/aspeed-bmc-opp-romulus.dts

@@ -35,6 +35,13 @@ coldfire_memory: codefire_memory@9ef00000 {
 			reg = <0x9ef00000 0x00100000>;
 			no-map;
 		};
+
+		gfx_memory: framebuffer {
+			size = <0x01000000>;
+			alignment = <0x01000000>;
+			compatible = "shared-dma-pool";
+			reusable;
+		};
 	};
 
 	leds {
@@ -238,6 +245,7 @@ &vuart {
 
 &gfx {
 	status = "okay";
+	memory-region = <&gfx_memory>;
 };
 
 &pinctrl {

arch/arm/boot/dts/aspeed-bmc-opp-witherspoon.dts

@@ -26,6 +26,13 @@ flash_memory: region@98000000 {
 			no-map;
 			reg = <0x98000000 0x04000000>; /* 64M */
 		};
+
+		gfx_memory: framebuffer {
+			size = <0x01000000>;
+			alignment = <0x01000000>;
+			compatible = "shared-dma-pool";
+			reusable;
+		};
 	};
 
 	gpio-keys {
@@ -565,6 +572,7 @@ &vuart {
 
 &gfx {
 	status = "okay";
+	memory-region = <&gfx_memory>;
 };
 
 &pinctrl {