PCI/MSI: Remove unused pci_irq_get_node()

The function pci_irq_get_node() is not used by anyone in the tree, so just
delete it.

Link: https://lore.kernel.org/r/20191014100452.GA6699@kroah.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Andrew Murray <andrew.murray@arm.com>