drm: msm: dp: add topology support for DisplayPort modes

This changes adds support in DisplayPort driver to provide
topology information of each display mode supported by
the device.

CRs-Fixed: 2020938
Change-Id: I5af71a5478b114853eeb83257c3a804722e8b105
Signed-off-by: Tatenda Chipeperekwa <tatendac@codeaurora.org>