vfio: platform: add dev_info on device reset

It might be helpful for the end-user to check the device reset
function was found by the vfio platform reset framework.

Lets store a pointer to the struct device in vfio_platform_device
and trace when the reset function is called or not found.

Signed-off-by: Eric Auger <[e-mail]>
Signed-off-by: Alex Williamson <[e-mail]>

drivers/vfio/platform/vfio_platform_common.c

···
 	mutex_lock(&driver_lock);
 
 	if (!(--vdev->refcnt)) {
-		if (vdev->reset)
+		if (vdev->reset) {
+			dev_info(vdev->device, "reset\n");
 			vdev->reset(vdev);
+		} else {
+			dev_warn(vdev->device, "no reset function found!\n");
+		}
 		vfio_platform_regions_cleanup(vdev);
 		vfio_platform_irq_cleanup(vdev);
 	}
···
 		if (ret)
 			goto err_irq;
 
-		if (vdev->reset)
+		if (vdev->reset) {
+			dev_info(vdev->device, "reset\n");
 			vdev->reset(vdev);
+		} else {
+			dev_warn(vdev->device, "no reset function found!\n");
+		}
 	}
 
 	vdev->refcnt++;
···
 		pr_err("VFIO: cannot retrieve compat for %s\n", vdev->name);
 		return -EINVAL;
 	}
+
+	vdev->device = dev;
 
 	group = iommu_group_get(dev);
 	if (!group) {

drivers/vfio/platform/vfio_platform_private.h

···
 	struct module			*parent_module;
 	const char			*compat;
 	struct module			*reset_module;
+	struct device			*device;
 
 	/*
 	 * These fields should be filled by the bus specific binder