ARM: dts: exynos/dp: remove some properties that deprecated by analogix_dp driver

After exynos_dp have been split the common IP code into analogix_dp driver,
the analogix_dp driver have deprecated some Samsung platform properties which
could be dynamically parsed from EDID/MODE/DPCD message, so this is an update
for Exynos DTS file for dp-controller.

Beside the backward compatibility is fully preserved, so there are no
bisectability break that make this change in a separate patch.

Reviewed-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Tested-by: Javier Martinez Canillas <javier@osg.samsung.com>
Signed-off-by: Yakir Yang <ykk@rock-chips.com>