x86 platform drivers: add POWER_SUPPLY to selected drivers for Dell

The Kconfig loop detection goes crazy without this.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/platform/x86/Kconfig

@@ -83,8 +83,8 @@ config DELL_LAPTOP
 	depends on EXPERIMENTAL
 	depends on BACKLIGHT_CLASS_DEVICE
 	depends on RFKILL || RFKILL = n
-	depends on POWER_SUPPLY
 	depends on SERIO_I8042
+	select POWER_SUPPLY
 	select LEDS_CLASS
 	select NEW_LEDS
 	default n