vfio: make local function vfio_pci_intx_unmask_handler() static

vfio_pci_intx_unmask_handler() was not declared. It should be static.

Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

drivers/vfio/pci/vfio_pci_intrs.c

@@ -286,7 +286,8 @@ void vfio_pci_intx_mask(struct vfio_pci_device *vdev)
  * a signal is necessary, which can then be handled via a work queue
  * or directly depending on the caller.
  */
-int vfio_pci_intx_unmask_handler(struct vfio_pci_device *vdev, void *unused)
+static int vfio_pci_intx_unmask_handler(struct vfio_pci_device *vdev,
+					void *unused)
 {
 	struct pci_dev *pdev = vdev->pdev;
 	unsigned long flags;