[ARM] 4509/1: S3C: Create initial arch/arm/plat-s3c

Create the initial arch/arm/plat-s3c directory and start
linking it into the arch/arm build heirarchy ready to
receive the generic parts of the S3C24XX support to be
used when adding S3C6400 devices.

Signed-off-by: Ben Dooks <ben-linux@fluff.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>