ARM: S3C2440: Fix s3c2440 cpufreq compilation post move.

Fix compilation issue by moving s3c2440-cpufreq.c into mach-s3c2440 directory
Signed-off-by: NVasily Khoruzhick <anarsoul@gmail.com>
Signed-off-by: NBen Dooks <ben-linux@fluff.org>