ARM: imx: Switch to new sys-off handler API

Kernel now supports chained power-off handlers. Use
register_platform_power_off() that registers a platform level power-off
handler. Legacy pm_power_off() will be removed once all drivers and archs
are converted to the new sys-off API.

Signed-off-by: Andrew Davis <afd@ti.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

Author: glneo

arch/arm/mach-imx/pm-imx6.c

@@ -634,13 +634,11 @@ static void imx6_pm_stby_poweroff(void)
 
 static int imx6_pm_stby_poweroff_probe(void)
 {
-	if (pm_power_off) {
-		pr_warn("%s: pm_power_off already claimed  %p %ps!\n",
-			__func__, pm_power_off, pm_power_off);
+	if (register_platform_power_off(imx6_pm_stby_poweroff)) {
+		pr_warn("%s: platform power off already claimed!\n", __func__);
 		return -EBUSY;
 	}
 
-	pm_power_off = imx6_pm_stby_poweroff;
 	return 0;
 }