net: dsa: sja1105: Add of_node_put() before return

Fix following coccicheck warning:
./drivers/net/dsa/sja1105/sja1105_main.c:1193:1-33: WARNING: Function
for_each_available_child_of_node should have of_node_put() before return.

Early exits from for_each_available_child_of_node should decrement the
node reference counter.

Fixes: 9ca482a2 ("net: dsa: sja1105: parse {rx, tx}-internal-delay-ps properties for RGMII delays")
Signed-off-by: Wan Jiabing <wanjiabing@vivo.com>
Link: https://lore.kernel.org/r/20211021094606.7118-1-wanjiabing@vivo.com


Signed-off-by: Jakub Kicinski <kuba@kernel.org>