PCI: hv: Fix a crash in hv_pci_restore_msi_msg() during hibernation

In the Linux kernel, the following vulnerability has been resolved: PCI: hv: Fix a crash in hv_pci_restore_msi_msg() during hibernation When a Linux VM with an assigned PCI device runs on Hyper-V, if the PCI device driver is not loaded yet (i.e. MSI-X/MSI is not enabled on the device yet), doing a VM hibernation triggers a panic in hv_pci_restore_msi_msg() -> msi_lock_descs(&pdev->dev), because pdev->dev.msi.data is still NULL. Avoid the panic by checking if MSI-X/MSI is enabled.