power: Add simple poweroff-gpio driver

Given appropriate devicetree bindings, this driver registers a
pm_power_off function to set a GPIO line high/low to power down
your board.

Signed-off-by: Jamie Lentin <jm@lentin.co.uk>
Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Tested-by:Simon Baatz <gmbnomis@gmail.com>
Signed-off-by: Jason Cooper <jason@lakedaemon.net>
diff --git a/drivers/power/Kconfig b/drivers/power/Kconfig
index 49a8939..b1d956d 100644
--- a/drivers/power/Kconfig
+++ b/drivers/power/Kconfig
@@ -335,6 +335,9 @@
 	help
 	  Say Y to enable battery temperature measurements using
 	  thermistor connected on BATCTRL ADC.
+
+source "drivers/power/reset/Kconfig"
+
 endif # POWER_SUPPLY
 
 source "drivers/power/avs/Kconfig"