sdm: add support for windowed display

- window display feature is displaying framebuffer
  content in a given rectangle on panel.
- fill remaining area with default color i.e. black.
- inform SF with reduced display size but SDM
  will see the mixer resolution is equal to panel.
- window rectangle can be set using below property
     vendor.display.window_rect = 250,250,250,250

CRs-Fixed: 2200594
Change-Id: Ib4cd4ccd6839370b568dbcdbadcdd81cfae88af9
5 files changed