sunxi: Implement poweroff support for axp152 pmic

Adds poweroff support for axp152 pmic.

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 e86dd72..de32828 100644
--- a/drivers/power/Kconfig
+++ b/drivers/power/Kconfig
@@ -20,6 +20,7 @@
 config AXP152_POWER
 	boolean "axp152 pmic support"
 	depends on MACH_SUN5I
+	select CMD_POWEROFF
 	---help---
 	Select this to enable support for the axp152 pmic found on most
 	A10s boards.