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 <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]'
Signed-off-by: Arnd Bergmann <[e-mail]>

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

···
 		};
 	};
 
-	memory {
+	memory@0 {
 		linux,usable-memory = <0x0 0x1f800000>;
 		available = <0xcf000 0x1ef31000 0x1000 0xbf000>;
 		reg = <0x0 0x20000000>;