Pull backlight updates from Lee Jones:
 "Core Framework:
   - Report correct error status to user

  Fix-ups:
   - Move Backlight headers out of I2C (adp8860, adp8870)"

* tag 'backlight-next-4.13' of git://git.kernel.org/pub/scm/linux/kernel/git/lee/backlight:
  video: adp8870: move header file out of I2C realm
  backlight: adp8860: Move header file out of I2C realm
  backlight: Report error on failure