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: 134d9c5 ("dmaengine: dw: dmamux: Introduce RZN1 DMA router support")
Cc: stable@vger.kernel.org	# 5.19
Cc: Miquel Raynal <miquel.raynal@bootlin.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
Reviewed-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://patch.msgid.link/20251117161258.10679-6-johan@kernel.org
Signed-off-by: Vinod Koul <vkoul@kernel.org>

Author: jhovold

drivers/dma/dw/rzn1-dmamux.c

@@ -90,7 +90,7 @@ static void *rzn1_dmamux_route_allocate(struct of_phandle_args *dma_spec,
 
 	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);
@@ -103,6 +103,8 @@ static void *rzn1_dmamux_route_allocate(struct of_phandle_args *dma_spec,
 
 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: