drm/vc4: Prefix 'struct exec_info' with 'vc4_'

All the other vc4 structs in vc4_drv.h have vc4_ in front of them, and
it seems like just good style.

Signed-off-by: Eric Anholt <eric@anholt.net>
drm/vc4: Move the hang detection to a timer.

We're going to need to do this for async execution, so make the switch
now.

Since the detection is smarter now (it can see when you're making
progess through the lists), we can crank up the default timeout for
executing a job.

Signed-off-by: Eric Anholt <eric@anholt.net>
drm: Put an optional field in the driver struct for GEM obj struct size.

This allows a driver to derive from the CMA object without copying all
of the code.

Signed-off-by: Eric Anholt <eric@anholt.net>
vc4: Make VC4_SUBMIT_CL return immediately, and add wait ioctls.

This allows userland to start queuing up the next command lists while
the current one is executing.

Signed-off-by: Eric Anholt <eric@anholt.net>