PCI: Disable MSI for Freescale Layerscape PCIe RC mode

The Freescale PCIe controller advertises the MSI/MSI-X capability in both
RC and Endpoint mode, but in RC mode it doesn't support MSI/MSI-X by
itself; it can only transfer MSI/MSI-X from downstream devices.

Add a quirk to prevent use of MSI/MSI-X in RC mode.

Signed-off-by: Hou Zhiqiang <Zhiqiang.Hou@nxp.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Minghuan Lian <minghuan.Lian@nxp.com>