vfio/pci: Trace vfio_set_irq_signaling() failure in vfio_msix_vector_release()

Report an error in case we fail to set a trigger action
on any VFIO_PCI_MSIX_IRQ_INDEX subindex. This might be
useful in debugging a device that is not working properly.
Signed-off-by: NEric Auger <eric.auger@redhat.com>
Reported-by: Coverity (CID 1402196)
Signed-off-by: NAlex Williamson <alex.williamson@redhat.com>

hw/vfio/pci.c

@@ -551,9 +551,12 @@ static void vfio_msix_vector_release(PCIDevice *pdev, unsigned int nr)
      */
     if (vector->virq >= 0) {
         int32_t fd = event_notifier_get_fd(&vector->interrupt);
+        Error *err = NULL;
 
-        vfio_set_irq_signaling(&vdev->vbasedev, VFIO_PCI_MSIX_IRQ_INDEX, nr,
-                               VFIO_IRQ_SET_ACTION_TRIGGER, fd, NULL);
+        if (vfio_set_irq_signaling(&vdev->vbasedev, VFIO_PCI_MSIX_IRQ_INDEX, nr,
+                                   VFIO_IRQ_SET_ACTION_TRIGGER, fd, &err)) {
+            error_reportf_err(err, VFIO_MSG_PREFIX, vdev->vbasedev.name);
+        }
     }
 }