disp: msm: sde: add plane staging management for 4LM topologies

When a 4LM topology is used each plane attached to a CRTC
is tagged with a L/R layout value and an offset value
depending on where destination X coordinate lands on the display.
The layout information is used to determine SSPP to LM
pair mapping and local coordinate space.

This change also handles source-split and Z-order
validation checks for planes staged on different mixer
pairs.

Change-Id: I1b20223388e65fc36a8b379ad9df23a277fcd1a5
Signed-off-by: Amine Najahi <anajahi@codeaurora.org>