drivers/video/backlight/platform_lcd.c: add support for device tree based probe

This patch adds the of_match_table to platform-lcd driver to be
probed when platform-lcd device node is found in the device tree.

[akpm@linux-foundation.org: include of.h]
Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Cc: Richard Purdie <rpurdie@rpsys.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>