clk: samsung: add clock controller driver for s3c2412

This driver can handle the clock controller in the s3c2412 soc.

The clock structure is built according to the manuals of the included
SoCs and might include changes in comparison to the previous clock
structure.

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