ARM: S5PV210: Add sclk_dac, sclk_mixer and sclk_hdmi clocks

Add sclk_dac, sclk_mixer and sclk_hdmi clocks. These clocks
are of type 'struct clksrc_clk' and so have a corresponding
clock list. These clocks are also added to the list of
clocks to be registered at boot time.

Signed-off-by: Thomas Abraham <thomas.ab@samsung.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>