When a power domain is powered off on Exynos5420 SoC, the input clocks of
the devices attached to this power domain are re-parented to oscclk and
restored to the original parent after powering on the power domain.

So a reference to the input and parent clocks for the devices attached to
a power domain are needed to be able to do the re-parenting. The DISP1 pd
includes modules which uses the following clocks:

ACLK_200_DISP1 (MIXER and HDMILINK)
ACLK_300_DISP1 (FIMD1)
ACLK_400_DISP1 (Internal Buses)

Each of these clocks are generated as the output of a clock mux so add an
ID for all of these clock muxes and their parents to be referenced in the
DISP1 power domain device node.
Signed-off-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
Acked-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Acked-by: Michael Turquette <mturquette@linaro.org>
Signed-off-by: Kukjin Kim <kgene@kernel.org>