ARM: dts: bcm283x: Add 32-bit enable method for SMP

This patch adds the missing 32-bit enable method for SMP on BCM2836 and
BCM2837. The BCM2837 already has an enabled method, but this one only
works for 64-bit.
Signed-off-by: NStefan Wahren <stefan.wahren@i2se.com>
Tested-by: NEric Anholt <eric@anholt.net>

arch/arm/boot/dts/bcm2836.dtsi

@@ -36,6 +36,7 @@
 	cpus: cpus {
 		#address-cells = <1>;
 		#size-cells = <0>;
+		enable-method = "brcm,bcm2836-smp";
 
 		v7_cpu0: cpu@0 {
 			device_type = "cpu";

arch/arm/boot/dts/bcm2837.dtsi

@@ -30,6 +30,7 @@
 	cpus: cpus {
 		#address-cells = <1>;
 		#size-cells = <0>;
+		enable-method = "brcm,bcm2836-smp"; // for ARM 32-bit
 
 		cpu0: cpu@0 {
 			device_type = "cpu";