dmaengine: at_hdmac: add missing put_device() call in at_dma_xlate()

If of_find_device_by_node() succeed, at_dma_xlate() doesn't have a
corresponding put_device(). Thus add put_device() to fix the exception
handling for this function implementation.

Fixes: bbe89c8e3d ("at_hdmac: move to generic DMA binding")
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Link: https://lore.kernel.org/r/20200817115728.1706719-3-yukuai3@huawei.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

drivers/dma/at_hdmac.c

@@ -1657,8 +1657,10 @@ static struct dma_chan *at_dma_xlate(struct of_phandle_args *dma_spec,
 	dma_cap_set(DMA_SLAVE, mask);
 
 	atslave = kmalloc(sizeof(*atslave), GFP_KERNEL);
-	if (!atslave)
+	if (!atslave) {
+		put_device(&dmac_pdev->dev);
 		return NULL;
+	}
 
 	atslave->cfg = ATC_DST_H2SEL_HW | ATC_SRC_H2SEL_HW;
 	/*
@@ -1687,8 +1689,10 @@ static struct dma_chan *at_dma_xlate(struct of_phandle_args *dma_spec,
 	atslave->dma_dev = &dmac_pdev->dev;
 
 	chan = dma_request_channel(mask, at_dma_filter, atslave);
-	if (!chan)
+	if (!chan) {
+		put_device(&dmac_pdev->dev);
 		return NULL;
+	}
 
 	atchan = to_at_dma_chan(chan);
 	atchan->per_if = dma_spec->args[0] & 0xff;