Revert "backlight: lm3630: Make backlight dimmer configurable"

This reverts commit b34e7175920aa02195845578876fade405506f7b.
backlight: fix a bug where the screen would be completely dark or near darkness with backlight_dimmer enabled when the display dimmed. The brightness level can't be any lower than dev->min_brightness and previous code allowed that to happen, so fix it.

Signed-off-by: franciscofranco <franciscofranco.1990@gmail.com>
backlight: clean the code.

Signed-off-by: franciscofranco <franciscofranco.1990@gmail.com>
backlight: add minimum backlight brightness module param.

Signed-off-by: franciscofranco <franciscofranco.1990@gmail.com>
backlight: scale max current when the brightness level is below 15 instead of using always 0.

Signed-off-by: franciscofranco <franciscofranco.1990@gmail.com>