drm/nouveau: fix thinko in channel locking in semaphore path

		return nouveau_fence_wait(fence, NULL, false, false);

	}

	/* try to take wchan's mutex, if we can't take it right away

	/* try to take chan's mutex, if we can't take it right away

	 * we have to fallback to software sync to prevent locking

	 * order issues

	 */

	if (!mutex_trylock(&wchan->mutex)) {

	if (!mutex_trylock(&chan->mutex)) {

		free_semaphore(&sema->ref);

		return nouveau_fence_wait(fence, NULL, false, false);

	}

	/* Make wchan wait until it gets signalled */

	ret = emit_semaphore(wchan, NV_SW_SEMAPHORE_ACQUIRE, sema);

	mutex_unlock(&wchan->mutex);

	if (ret)

		goto out;

	/* Signal the semaphore from chan */

	ret = emit_semaphore(chan, NV_SW_SEMAPHORE_RELEASE, sema);

	mutex_unlock(&chan->mutex);

out:

	kref_put(&sema->ref, free_semaphore);

	return ret;