[ARM] S3C24A0: Initial architecture support files

Initial architecture support for the S3C24A0 ARCH_S3C24A0.

We don't yet add an kconfig entry in the main arch/arm/Kconfig
file as the series is not complete, so that is left until enough
support is in to be useful.

Signed-off-by: Ben Dooks <ben-linux@fluff.org>