drm/sched: Mark fair policy as experimental

drm/sched: Mark fair policy as experimental

Mark the fair policy as experimental until reported regressions are
addressed.

Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@igalia.com>
Cc: Luke.Wildhardt@proton.me
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: Danilo Krummrich <dakr@kernel.org>
Cc: Philipp Stanner <phasta@kernel.org>
Cc: Christian König <ckoenig.leichtzumerken@gmail.com>
Signed-off-by: Tvrtko Ursulin <tursulin@ursulin.net>
Link: https://lore.kernel.org/r/20260811163139.99746-20-tvrtko.ursulin@igalia.com