ARM: S3C2412: Fix typo in CONFIG_CPU_S3C2412_ONLY definition

Dependency on (CPU_S3C2416 is not selected) was defined as "!CPU_2416",
instead of "!CPU_S3C2416". Fix it.

Signed-off-by: Yauhen Kharuzhy <jekhor@gmail.com>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>