drm/msm/dsi: Return more timings from PHY to host

The DSI host is required to configure more timings calculated
in PHY. By introducing a shared structure, this change allows
more timing information passed from PHY to host.

Signed-off-by: Hai Li <hali@codeaurora.org>
Signed-off-by: Archit Taneja <architt@codeaurora.org>
Signed-off-by: Rob Clark <robdclark@gmail.com>