virtio: Add support for no-reset virtio PCI PM

If a virtio_pci_device supports native PCI power management and has the
No_Soft_Reset bit set, then skip resetting and reinitializing the device
when suspending and restoring the device. This allows system-wide low
power states like s2idle to be used in systems with stateful virtio
devices that can't simply be re-initialized (e.g. virtio-fs).

Signed-off-by: David Stevens <stevensd@chromium.org>
Message-Id: <20231208070754.3132339-1-stevensd@chromium.org>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>