mfd: twl4030-power: Use 'ti,system-power-controller' as alternative way to support system power off

ti,system-power-controller is more or less the standard way of
indicating that the PMIC is the system wide power controller and hence
may be used to switch off the system. Almost ALL TI PMIC drivers and
many Maxim PMIC drivers follow the same style.

So support 'ti,system-power-controller' in addition to the usual
'ti,use_poweroff' to indicate that the PMIC instance has control for
switching off the system.
Signed-off-by: NNishanth Menon <nm@ti.com>
Acked-by: NTony Lindgren <tony@atomide.com>
Signed-off-by: NLee Jones <lee.jones@linaro.org>

drivers/mfd/twl4030-power.c

@@ -627,6 +627,9 @@ static bool twl4030_power_use_poweroff(const struct twl4030_power_data *pdata,
 	if (pdata && pdata->use_poweroff)
 		return true;
 
+	if (of_property_read_bool(node, "ti,system-power-controller"))
+		return true;
+
 	if (of_property_read_bool(node, "ti,use_poweroff"))
 		return true;