If the framebuffer has requested blanking, turn the backlight down. Also
offer the user the option to do this.
Reported-by: NMichal Pecio <michal.pecio@gmail.com>
Signed-off-by: NCarlos Corbacho <carlos@strangeworlds.co.uk>
Signed-off-by: NLen Brown <len.brown@intel.com>
Signed-off-by: NAndi Kleen <ak@linux.intel.com>