fb: backlight: add the Himax HX-8357B LCD controller

Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Cc: Jingoo Han <jg1.han@samsung.com>
Cc: Shawn Guo <shawn.guo@linaro.org>
Cc: Brian Lilly <brian@crystalfontz.com>
Cc: Richard Purdie <rpurdie@rpsys.net>
Cc: Florian Tobias Schandinat <FlorianSchandinat@gmx.de>
Cc: Grant Likely <grant.likely@secretlab.ca>
Cc: Rob Herring <rob.herring@calxeda.com>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>