aspeed: Cleanup ast2500-u-boot.dtsi Device Tree

Remove unnecessary apb and ahb nodes and just override necessary
nodes/values.

Signed-off-by: Maxim Sloyko <maxims@google.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

arch/arm/dts/ast2500-u-boot.dtsi

@@ -34,32 +34,33 @@
 
 		apb {
 			u-boot,dm-pre-reloc;
+		};
 
-			timer: timer@1e782000 {
+	};
-				u-boot,dm-pre-reloc;
+};
-			};
 
-			uart1: serial@1e783000 {
+&uart1 {
-				clocks = <&scu PCLK_UART1>;
+	clocks = <&scu PCLK_UART1>;
-			};
+};
 
-			uart2: serial@1e78d000 {
+&uart2 {
-				clocks = <&scu PCLK_UART2>;
+	clocks = <&scu PCLK_UART2>;
-			};
+};
 
-			uart3: serial@1e78e000 {
+&uart3 {
-				clocks = <&scu PCLK_UART3>;
+	clocks = <&scu PCLK_UART3>;
-			};
+};
 
-			uart4: serial@1e78f000 {
+&uart4 {
-				clocks = <&scu PCLK_UART4>;
+	clocks = <&scu PCLK_UART4>;
-			};
+};
 
-			uart5: serial@1e784000 {
+&uart5 {
-				clocks = <&scu PCLK_UART5>;
+	clocks = <&scu PCLK_UART5>;
-			};
+};
-		};
+
-	};
+&timer {
+	u-boot,dm-pre-reloc;
 };
 
 &mac0 {