ARM: SAMSUNG: Add clock types into platform data

This patch adds clock types into platform data to support
external clock divider instead of internal clock divider.
It is defined that what kinds of clock type is used in machine.

Signed-off-by: Jeongbae Seo <jeongbae.seo@samsung.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>