Do the same as commit 
a03a202e95fd ("dmaengine: failure to get a
specific DMA channel is not critical") to get rid of the following
messages during kernel boot:
  dmaengine_get: failed to get dma1chan0: (-22)
  dmaengine_get: failed to get dma1chan1: (-22)
  dmaengine_get: failed to get dma1chan2: (-22)
  dmaengine_get: failed to get dma1chan3: (-22)
  ..
Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Cc: Vinod Koul <vinod.koul@intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
                                list_del_rcu(&device->global_node);
                                break;
                        } else if (err)
-                               pr_err("%s: failed to get %s: (%d)\n",
+                               pr_debug("%s: failed to get %s: (%d)\n",
                                       __func__, dma_chan_name(chan), err);
                }
        }