drm/i95: Initialize active ring->pid to -1

Otherwise we print out spurious processes on unused rings in the error
state.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: stable@vger.kernel.org
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>

drivers/gpu/drm/i915/i915_gpu_error.c

@@ -888,14 +888,15 @@ static void i915_gem_record_rings(struct drm_device *dev,
 	for (i = 0; i < I915_NUM_RINGS; i++) {
 		struct intel_engine_cs *ring = &dev_priv->ring[i];
 
+		error->ring[i].pid = -1;
+
 		if (ring->dev == NULL)
 			continue;
 
 		error->ring[i].valid = true;
 
 		i915_record_ring_state(dev, ring, &error->ring[i]);
 
-		error->ring[i].pid = -1;
 		request = i915_gem_find_active_request(ring);
 		if (request) {
 			/* We need to copy these to an anonymous buffer