ARM: S3C24XX: add platform code for conversion to the common clock framework

This adds the necessary init functions to init the clocks from the common
clock framework and necessary CONFIG_SAMSUNG_CLOCK ifdefs around the legacy
clock code.

This also includes empty stubs for the *_setup_clocks functions that are
called from the cpufreq driver on resume.

Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Reviewed-by: Tomasz Figa <t.figa@samsung.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>