vfio: Mark expected switch fall-throughs

In preparation to enabling -Wimplicit-fallthrough, mark switch cases
where we are expecting to fall through.

Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

drivers/vfio/pci/vfio_pci.c

@@ -789,7 +789,7 @@ static long vfio_pci_ioctl(void *device_data,
 		case VFIO_PCI_ERR_IRQ_INDEX:
 			if (pci_is_pcie(vdev->pdev))
 				break;
-		/* pass thru to return error */
+		/* fall through */
 		default:
 			return -EINVAL;
 		}

drivers/vfio/vfio_iommu_type1.c

@@ -1601,6 +1601,7 @@ static void *vfio_iommu_type1_open(unsigned long arg)
 		break;
 	case VFIO_TYPE1_NESTING_IOMMU:
 		iommu->nesting = true;
+		/* fall through */
 	case VFIO_TYPE1v2_IOMMU:
 		iommu->v2 = true;
 		break;