ARM: dts: msm: move sdp_dp device to sde dtsi for sdm845

Move the DP entries that are chipset-specific rather
than panel-specific to the top level sde dtsi file.

Change-Id: I1f2ce5c7f897a7d86c9a77b8523660b8439dc280
Signed-off-by: Ingrid Gallardo <ingridg@codeaurora.org>