Add support for 4 layer mixer staging logic

Currently plane staging logic assumes that only
2 planes (L/R) are required to drive the display.
When a 4LM topology is used, 4 adjacent planes are
needed to cover wider display resolutions.

This changes offsets plane src_x and dest_x coordinates
based on plane index and removes L/R assumption. It also
adds 4LM and VDC based topologies.

CRs-Fixed: 2672665
Test: boot-up test on 2LM and 4LM topologies

Change-Id: If33e9b22b5545e2187ab614eed390dfe09af56a9