mpc85xx: p1010: Fix Sophos RED 15w NAND partitions

This partially reverts 78d259e.
That commit broke mounting the root fs on Sophos RED 15w due to
partition size mismatch, and changed the partition sequence, causing
the OpenWrt partition numbers to change from mtd3:kernel/mtd4:ubi to
mtd4:kernel/mtd5:ubi.

Fixes: 78d259e ("mpc85xx: fix some dtc warnings")
(cherry-picked from commit 09e7b24)
Signed-off-by: Shine <[email protected]>
Link: openwrt/openwrt#21062
Signed-off-by: Hauke Mehrtens <[email protected]>

Author: Shine-

target/linux/mpc85xx/files/arch/powerpc/boot/dts/red-15w-rev1.dts

@@ -165,23 +165,19 @@
 					read-only;
 				};
 
+				partition@300000 {
+					reg = <0x300000 0x800000>;
+					label = "kernel";
+				};
+
+				partition@b00000 {
+					reg = <0xb00000 0x7500000>;
+					label = "ubi";
+				};
+
 				oem-partition@300000 {
 					reg = <0x300000 0x1900000>;
 					label = "sophos-os1";
-
-					compatible = "fixed-partitions";
-					#address-cells = <1>;
-					#size-cells = <1>;
-
-					partition@0 {
-						reg = <0x0 0x800000>;
-						label = "kernel";
-					};
-
-					partition@800000 {
-						reg = <0x800000 0x7500000>;
-						label = "ubi";
-					};
 				};
 
 				oem-partition@1c00000 {