fb: add s3c-fb driver for newer Samsung SoC framebuffer devices

Add support for the newer Samsung devices, such as found in the S3C2443,
S3C6400 or S3C6410 series SoC.

It currently does not support all the alpha- or chroma-key options but it
will support more exporting more than one framebuffer ready for adding
overlay and blending functions.

Signed-off-by: Ben Dooks <ben-linux@fluff.org>
Cc: Krzysztof Helt <krzysztof.h1@poczta.fm>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>