video: backlight: support s6e8ax0 panel driver based on MIPI DSI

An moled panel driver based MIPI DSI interface.  S6E8AX0 means it may
includes many other ldi controllers, for example, S6E8AA0, S6E8AB0, and so
on.

This patch can be modified depending on each panel properites.  For
example, second parameter of panel condition register can be changed
depending on ldi controller or amoled type.

[akpm@linux-foundation.org: fix Kconfig syntax error]
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Donghwa Lee <dh09.lee@samsung.com>
Signed-off-by: Inki Dae <inki.dae@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Cc: Jingoo Han <jg1.han@samsung.com>
Cc: Richard Purdie <rpurdie@rpsys.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Florian Tobias Schandinat <FlorianSchandinat@gmx.de>