clk: samsung: Add clock driver for S5PV210 and compatible SoCs

This patch adds new, Common Clock Framework-based clock driver for Samsung
S5PV210 and compatible SoCs. The driver is just added, without enabling it yet.

Signed-off-by: Mateusz Krawczuk <m.krawczuk@partner.samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
[t.figa: Added support for other SoC variants and clock output. Fixed
remaining minor issues.]
Signed-off-by: Tomasz Figa <t.figa@samsung.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>