spi: cadence: Add of_node_put() before return

Fix following coccicheck warning:
./drivers/spi/spi-cadence-xspi.c:490:1-23: WARNING: Function
for_each_child_of_node should have of_node_put() before return

Early exits from for_each_child_of_node should decrement the
node reference counter.
Signed-off-by: Wan Jiabing <wanjiabing@vivo.com>
Link: https://lore.kernel.org/r/20211015033919.5915-1-wanjiabing@vivo.comSigned-off-by: Mark Brown <broonie@kernel.org>

drivers/spi/spi-cadence-xspi.c

@@ -493,9 +493,11 @@ static int cdns_xspi_of_get_plat_data(struct platform_device *pdev)
 
 		if (of_property_read_u32(node_child, "reg", &cs)) {
 			dev_err(&pdev->dev, "Couldn't get memory chip select\n");
+			of_node_put(node_child);
 			return -ENXIO;
 		} else if (cs >= CDNS_XSPI_MAX_BANKS) {
 			dev_err(&pdev->dev, "reg (cs) parameter value too large\n");
+			of_node_put(node_child);
 			return -ENXIO;
 		}
 	}