ARM: S3C2412: Update memory register mapping and definitions

Update the mapping of the memory controler registers and
add the missing definitions of the register block for the
SSMC.

The register contents definitions can be found in the pl093
header.

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