ARM: dts: mmp2-olpc-xo-1-75: Fix memory node name

It contains a reg property. Add its base to the node name.
Signed-off-by: Lubomir Rintel <lkundrak@v3.sk>
Link: https://lore.kernel.org/r/20210121034130.1381872-4-lkundrak@v3.sk'
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

arch/arm/boot/dts/mmp2-olpc-xo-1-75.dts

@@ -32,7 +32,7 @@ framebuffer@1fc00000 {
 		};
 	};
 
-	memory {
+	memory@0 {
 		linux,usable-memory = <0x0 0x1f800000>;
 		available = <0xcf000 0x1ef31000 0x1000 0xbf000>;
 		reg = <0x0 0x20000000>;