ARM: S3C24XX: Move mach-s3c2410/ cpufreq into mach-s3c24xx/

Basically, the cpufreq driver for s3c2410 should be implemented into
drivers/cpufreq, but we don't need to keep the mach-s3c2410 directory.
So this patch moves current cpufreq driver into mach-s3c24xx/.

Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>