cpufreq: s3c24xx: move cpufreq driver to drivers/cpufreq

This patch moves cpufreq driver of Samsung's ARM based
s3c24xx platform to drivers/cpufreq.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>