ARM: dts: mmp2-olpc-xo-1-75: Enable the GPU

Enable the 3D + 2D (GC860) GPU core.

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

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

···
 		};
 	};
 };
+
+&gpu {
+	status = "okay";
+};