ARM: dts: imx6ul: add pm_power_off support

i.MX6UL can be powered off by programming SNVS.

When long press ON/OFF button(5 seconds),
PMIC_ON_REQ pin will be set to low and external
PMIC will be powered off.

And system can be powered on by long press ON/OFF
button again.

Signed-off-by: Anson Huang <b20788@freescale.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>
diff --git a/arch/arm/boot/dts/imx6ul.dtsi b/arch/arm/boot/dts/imx6ul.dtsi
index c2eb3d4..96b00c6 100644
--- a/arch/arm/boot/dts/imx6ul.dtsi
+++ b/arch/arm/boot/dts/imx6ul.dtsi
@@ -429,6 +429,14 @@
 						     <GIC_SPI 20 IRQ_TYPE_LEVEL_HIGH>;
 				};
 
+				snvs_poweroff: snvs-poweroff {
+					compatible = "syscon-poweroff";
+					regmap = <&snvs>;
+					offset = <0x38>;
+					mask = <0x60>;
+					status = "disabled";
+				};
+
 				snvs_pwrkey: snvs-powerkey {
 					compatible = "fsl,sec-v4.0-pwrkey";
 					regmap = <&snvs>;