drm/msm/dsi-staging: use sde connector for dsi

Update the display manager and dsi driver to make use of the sde's
generic connector infrastructure. Replace DISPLAY_TYPE property
with a generic SDE_INFO property that contains one or more key+value
pairs.

Change-Id: I366ea44e2e03211424b9cfa7b713178f5d01490d
Signed-off-by: Clarence Ip <cip@codeaurora.org>