ARM: dts: aspeed: witherspoon: Update BMC partitioning

Add simplified partitions for BMC and alternate flash. Include these by
default in Witherspoon.

Signed-off-by: Edward A. James <[e-mail]>
Signed-off-by: Adriana Kobylak <[e-mail]>
Reviewed-by: Cédric Le Goater <[e-mail]>
Reviewed-by: Andrew Jeffery <[e-mail]>
Signed-off-by: Joel Stanley <[e-mail]>

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

···
 		status = "okay";
 		label = "bmc";
 		m25p,fast-read;
-#include "openbmc-flash-layout.dtsi"
+
+		partitions {
+			#address-cells = < 1 >;
+			#size-cells = < 1 >;
+			compatible = "fixed-partitions";
+			u-boot@0 {
+				reg = < 0 0x60000 >;
+				label = "u-boot";
+			};
+			u-boot-env@60000 {
+				reg = < 0x60000 0x20000 >;
+				label = "u-boot-env";
+			};
+			obmc-ubi@80000 {
+				reg = < 0x80000 0x1F80000 >;
+				label = "obmc-ubi";
+			};
+		};
 	};
 
 	flash@1 {
 		status = "okay";
-		label = "alt";
+		label = "alt-bmc";
 		m25p,fast-read;
+
+		partitions {
+			#address-cells = < 1 >;
+			#size-cells = < 1 >;
+			compatible = "fixed-partitions";
+			u-boot@0 {
+				reg = < 0 0x60000 >;
+				label = "alt-u-boot";
+			};
+			u-boot-env@60000 {
+				reg = < 0x60000 0x20000 >;
+				label = "alt-u-boot-env";
+			};
+			obmc-ubi@80000 {
+				reg = < 0x80000 0x1F80000 >;
+				label = "alt-obmc-ubi";
+			};
+		};
+
 	};
 };