dmaengine: Remove unused declaration dma_chan_cleanup()

Commit f27c580c ("dmaengine: remove 'bigref' infrastructure")
removed the implementation but left declaration in place. Remove it.
Signed-off-by: Yue Haibing <yuehaibing@huawei.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20230809080012.22000-1-yuehaibing@huawei.comSigned-off-by: Vinod Koul <vkoul@kernel.org>

include/linux/dmaengine.h

@@ -517,8 +517,6 @@ static inline const char *dma_chan_name(struct dma_chan *chan)
 	return dev_name(&chan->dev->device);
 }
 
-void dma_chan_cleanup(struct kref *kref);
-
 /**
  * typedef dma_filter_fn - callback filter for dma_request_channel
  * @chan: channel to be reviewed