drm/scheduler: remove full_recover from drm_sched_start

drm/scheduler: remove full_recover from drm_sched_start

This was basically just another one of amdgpus hacks. The parameter
allowed to restart the scheduler without turning fence signaling on
again.

That this is absolutely not a good idea should be obvious by now since
the fences will then just sit there and never signal.

While at it cleanup the code a bit.

Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Matthew Brost <matthew.brost@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240722083816.99685-1-christian.koenig@amd.com