backlight: Kconfig cleanup

Cleanup the "depends on" logic by wrapping the affected config options in
appropriate if/endif blocks.

Remove all the "default n" since that is the default default.

Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Richard Purdie <rpurdie@linux.intel.com>

diff --cc drivers/video/backlight/Kconfig
Simple merge