ARM: dts: add clocks to hdmi dt node for exynos5250

Fix wrong clock numbers in hdmi dt node. Removed hdmiphy
clock which was a dummy clock earlier and not required now.
Also added mux clock to change the clock parent.

Signed-off-by: Rahul Sharma <rahul.sharma@samsung.com>
Reviewed-by: Tomasz Figa <t.figa@samsung.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>