sdm: Fix idle fallback logic.

- Trigger invalidate only if previous draw cycle was not composed completely
  using GPU.
- Fix dumpsys alignment.
- Remove invalid fd warning logs for solid fill with no buffers.
- Return error if fd for output buffer for virtual display is invalid.

CRs-Fixed: 870262
Change-Id: I083c6aa3e6c826754439201cc975e03371396217
5 files changed