drm/i915/perf: destroy stream on sample_flags mismatch

If we were to ever encounter a sample_flags mismatch we need to ensure
we destroy the stream when we bail.

Fixes: d7965152 ("drm/i915: Enable i915 perf stream for Haswell OA unit")
Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Cc: Robert Bragg <robert@sixbynine.org>
Reviewed-by: Mika Kuoppala <mika.kuoppala@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170327203459.18398-1-matthew.auld@intel.com

drivers/gpu/drm/i915/i915_perf.c

@@ -1705,7 +1705,7 @@ i915_perf_open_ioctl_locked(struct drm_i915_private *dev_priv,
 	 */
 	if (WARN_ON(stream->sample_flags != props->sample_flags)) {
 		ret = -ENODEV;
-		goto err_alloc;
+		goto err_flags;
 	}
 
 	list_add(&stream->link, &dev_priv->perf.streams);
@@ -1728,6 +1728,7 @@ i915_perf_open_ioctl_locked(struct drm_i915_private *dev_priv,
 
 err_open:
 	list_del(&stream->link);
+err_flags:
 	if (stream->ops->destroy)
 		stream->ops->destroy(stream);
 err_alloc: