MIPS: Loongson64: Add of_node_put() before break

Fix following coccicheck warning:
./arch/mips/loongson64/init.c:174:1-22: WARNING: Function
for_each_node_by_name should have of_node_put() before break

Early exits from for_each_node_by_name should decrement the
node reference counter.

Signed-off-by: Wan Jiabing <wanjiabing@vivo.com>
Reviewed-by: Huacai Chen <chenhuacai@kernel.org>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>