power: supply: KConfig cleanup default n

The "default n" is not needed as it is, well, default. Clean
the KConfig by removing "default n".

Signed-off-by: Matti Vaittinen <matti.vaittinen@fi.rohmeurope.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>