drm/i915: Stop asserting on set-wedged vs nop_submit_request ordering

drm/i915: Stop asserting on set-wedged vs nop_submit_request ordering

Since the removal of the stop_machine(), it is allowed and expected for
the nop_submit_request() and nop_complete_submit_request() to run in
parallel to the i915_gem_set_wedged() processing. As such we can no
longer assert that i915_gem_set_wedged() has completed inside the
stop_machine prior to the individual nop_submit_request execution.

Fixes: 520ce5dd9558 ("drm/i915: Use rcu instead of stop_machine in set_wedged")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Daniel Vetter <daniel.vetter@intel.com>
Cc: Mika Kuoppala <mika.kuoppala@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171012204019.3557-1-chris@chris-wilson.co.uk
Reviewed-by: Daniel Vetter <daniel.vetter@intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala@intel.com>