um: switch to use of drivers/Kconfig

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Richard Weinberger <richard@nod.at>
diff --git a/drivers/power/Kconfig b/drivers/power/Kconfig
index 57de051..9f88641 100644
--- a/drivers/power/Kconfig
+++ b/drivers/power/Kconfig
@@ -70,6 +70,7 @@
 
 config BATTERY_DS2780
 	tristate "DS2780 battery driver"
+	depends on HAS_IOMEM
 	select W1
 	select W1_SLAVE_DS2780
 	help