devices: virtio: pci device: convert to using IrqLevelEvent
devices: virtio: pci device: convert to using IrqLevelEvent

This converts VirtioPciDevice to use IrqLevelEvent.

BUG=None
TEST=./tools/presubmit

Change-Id: Ifcc72c1dd9e1fb1f116ab78f3639363dfb0136b3
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crosvm/+/3548056
Reviewed-by: Daniel Verkamp <72bc170b46ec491f7bdd4359a1c0bfed274de40c@chromium.org>
Tested-by: kokoro <2ac7b1f3fa578934c95181d4272be0d3bca00121@google.com>
Commit-Queue: Dmitry Torokhov <10a8c465cefc9bdd6c925e26964d23c90f1141cc@chromium.org>

google/crosvm,google/crosvm,google/crosvm,google/crosvm