PCI: microchip: Fix refcount leak in mc_pcie_init_irq_domains()

PCI: microchip: Fix refcount leak in mc_pcie_init_irq_domains()

of_get_next_child() returns a node pointer with refcount incremented, so we
should use of_node_put() on it when we don't need it anymore.

mc_pcie_init_irq_domains() only calls of_node_put() in the normal path,
missing it in some error paths.  Add missing of_node_put() to avoid
refcount leak.

Fixes: 6f15a9c9f941 ("PCI: microchip: Add Microchip PolarFire PCIe controller driver")
Link: https://lore.kernel.org/r/20220605055123.59127-1-linmq006@gmail.com
Signed-off-by: Miaoqian Lin <linmq006@gmail.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Rob Herring <robh@kernel.org>