drm_hwcomposer: Add non-blocking commit support

This change fixes FPS drop on multidisplay devices.

Also in some cases it gives graphics pipeline more free time to draw
in advance.

Signed-off-by: Roman Stratiienko <roman.o.stratiienko@globallogic.com>
2 jobs for add-async-commit-support in 11 minutes and 8 seconds (queued for 1 second)