backlight: Value of ILI9320_RGB_IF2 register should not be hardcoded

It is stored in the board specific file
  ./arch/arm/mach-s3c2412/mach-jive.c
as .rgb_if2.

Actually, the value is correct, only semantic is wrong.

Signed-off-by: Denis V. Lunev <den@openvz.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Richard Purdie <rpurdie@linux.intel.com>