ARM: S3C64XX: add frame buffer support for mach-mini6410

Add support for frame buffer device for mach-mini6410.
Patch also adds support for feature string parsing
for mini6410. The feature string is kernel command
line passed and currently lets select only LCD
configuration. At the moment there is support for
two LCD configurations - 4.3" and 7.0". Feature
parser is mach-mini2440 based.

Signed-off-by: Darius Augulis <augulis.darius@gmail.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>