msm: mdss: Update the postprocessing ops using mdss revision

Post processing ops for feature is dependent on the mdss revision.
When the probe of mdp post processing driver is called, driver
should hook the function pointers based on the mdss revision.

CRs-Fixed: 985286
Change-Id: I689f291902d45d5333de0b49f51166a1343c3d06
Signed-off-by: Gopikrishnaiah Anandan <agopik@codeaurora.org>
Signed-off-by: Ping Li <pingli@codeaurora.org>