Building the tegra PCIe host driver without MSI results in a link
failure:
drivers/pci/host/pci-tegra.o:(.data+0x70): undefined reference to
`pci_msi_unmask_irq'
drivers/pci/host/pci-tegra.o:(.data+0x74): undefined reference to
`pci_msi_mask_irq'
This adds the same dependency that everyone else uses.