This patch updates the backlight nodes to improve the support and describe
better how hardware is done. The changes done were:
* Use PWM_POLARITY_INVERTED instead of the hardcoded number.
* Add pinctrl configuration.
* Add the enable gpio definition.
* Add the power supply definition.
* Add more brightness levels.
Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com> Signed-off-by: Tony Lindgren <tony@atomide.com>