[ARM] 4521/2: S3C: Reorganise VA mapping headers

Reorganise the definition of the virtual addresses
used into a common header and update the users to
rename S3C2410 items into a more common S3C defined
macros.

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