Fixes:
- compiler warnings on unused variables
- comparing correct types
- optimized calculations

The framerate calculation previously done in v4l2 access input was always late. Reworked the calculation to move closer to the requested framerate by setting a new frame grab deadline based on grab-date + duration + late (deadline miss). On a fast CPU it will not make much difference, but on a slow CPU the algorithm will grab frames based on FPS settings.

cleanup commit-id: dfa08f13