Revert "ARM: dts: rockchip: temporarily disable smp on rk3288"

We now have the physical-timers patches lined up as a dependency in this same
branch, so we can revert the temporary disablement.

This reverts commit b77d43943ea83997c6c37b8831d1561981d499c5.

Signed-off-by: Olof Johansson <olof@lixom.net>
diff --git a/arch/arm/boot/dts/rk3288.dtsi b/arch/arm/boot/dts/rk3288.dtsi
index acb6a2f..8313077 100644
--- a/arch/arm/boot/dts/rk3288.dtsi
+++ b/arch/arm/boot/dts/rk3288.dtsi
@@ -47,6 +47,7 @@
 	cpus {
 		#address-cells = <1>;
 		#size-cells = <0>;
+		enable-method = "rockchip,rk3066-smp";
 		rockchip,pmu = <&pmu>;
 
 		cpu0: cpu@500 {