sunxi: Implement poweroff support for axp209 pmic

Adds poweroff support for axp209 pmic.

Signed-off-by: Michael van Slingerland <michael@deviousops.nl>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Ian Campbell <ijc@hellion.org.uk>
diff --git a/drivers/power/Kconfig b/drivers/power/Kconfig
index de32828..52c9e61 100644
--- a/drivers/power/Kconfig
+++ b/drivers/power/Kconfig
@@ -28,6 +28,7 @@
 config AXP209_POWER
 	boolean "axp209 pmic support"
 	depends on MACH_SUN4I || MACH_SUN5I || MACH_SUN7I
+	select CMD_POWEROFF
 	---help---
 	Select this to enable support for the axp209 pmic found on most
 	A10, A13 and A20 boards.