ARM: EXYNOS: register master power domain for genpd from DT

ARM: EXYNOS: register master power domain for genpd from DT

There is one case for EXYNOS4412 that mixer needs LCD0 power domain as
well as TV power domain. If disable LCD0 power domain, mixer occurs
underflow of mixer graphic layer0 line buffer and we can't output normal
data from hdmi. I don't know why mixer has dependency of LCD0 power
domain.

We can control the dependency as LCD0 power domain register to master of
TV power domain on genpd framework.

Change-Id: I71ef5bba37393d2e00c4dd7ea3f7da09d72e8db7
Signed-off-by: Joonyoung Shim <jy0922.shim@samsung.com>