FB/S3C2410: ensure S3C2410 framebuffer clears initial memory to black

Change the initial pattern in the s3c2410 framebuffer driver
to black.

Signed-off-by: Ben Dooks <ben-linux@fluff.org>
Cc: "Antonino A. Daplas" <adaplas@pol.net>
Cc: Vincent Sanders <vince@simtec.co.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>