hwc: Extend PTOR feature for two layers

- Consider two smallest layers for PTOR feature which uses MDP comp.
- These two layers are rendered on a buffer and are queued to MDP
  to acheive full MDP Composition
- This helps to acheive performance enhancement

Change-Id: I43d9306ff19cd2d7a410c885316523965a44cbd4
6 files changed