[ARM] 4164/1: S3C2412: Add SMDK2412 to SMDK2413

Our current support for the SMDK2413 is the same
as the SMDK2412 (which is very similar), so add
SMDK2412 to the list of machines that mach-smdk2413.c
supports

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