powerpc/44x: Add of_node_put() when break out from for_each

In ppc47x_init_irq(), we need to call of_node_put() when there is
a break during the iteration of for_each_node_with_property() which
will automatically increase and decrease the refcount.

Signed-off-by: Liang He <windhl@126.com>
[mpe: mpic_alloc() takes its own reference]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220701133126.243102-1-windhl@126.com