Revert "omxil: new way to wait for omxbuffers to be returned"

This reverts commit 6e695e4aa967df34c11bf08a3346c4eb4038b1f6.

Conflicts:
	modules/codec/omxil/omxil.c
	modules/codec/omxil/omxil.h
fix FreeBuffers when using hwbuf.

- only wait for buffers we own and that we passed to OMX.
- Merge HwBuffer_Stop and InvalidatePictures.