drm/msm/dsi-staging: update topology parsing logic

The kernel command-line string is changed and the
parsing will be done in DSI display module. Add
support to enable topology parsing in DSI
display module.

Change-Id: I4864bedf69724c746224eedc064b6144b61ded50
Signed-off-by: Chandan Uddaraju <chandanu@codeaurora.org>