dmaengine: dw: dmamux: fix OF node leak on route allocation failure

Make sure to drop the reference taken to the DMA master OF node also on
late route allocation failures.

Fixes: 134d9c52fca2 ("dmaengine: dw: dmamux: Introduce RZN1 DMA router support")
Cc: [e-mail] # 5.19
Cc: Miquel Raynal <[e-mail]>
Signed-off-by: Johan Hovold <[e-mail]>
Reviewed-by: Miquel Raynal <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Vinod Koul <[e-mail]>

drivers/dma/dw/rzn1-dmamux.c

···
 
 	if (test_and_set_bit(map->req_idx, dmamux->used_chans)) {
 		ret = -EBUSY;
-		goto free_map;
+		goto put_dma_spec_np;
 	}
 
 	mask = BIT(map->req_idx);
···
 
 clear_bitmap:
 	clear_bit(map->req_idx, dmamux->used_chans);
+put_dma_spec_np:
+	of_node_put(dma_spec->np);
 free_map:
 	kfree(map);
 put_device: