hisi_acc_vfio_pci: Fix reference leak in hisi_acc_vfio_debug_init

The debugfs_lookup() function returns a dentry with an increased reference
count that must be released by calling dput().

Fixes: b398f91 ("hisi_acc_vfio_pci: register debugfs for hisilicon migration driver")
Cc: stable@vger.kernel.org
Signed-off-by: Miaoqian Lin <linmq006@gmail.com>
Reviewed-by: Longfang Liu <liulongfang@huawei.com>
Link: https://lore.kernel.org/r/20250901081809.2286649-1-linmq006@gmail.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

Author: Yuuoniy

drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c

@@ -1612,8 +1612,10 @@ static void hisi_acc_vfio_debug_init(struct hisi_acc_vf_core_device *hisi_acc_vd
 	}
 
 	migf = kzalloc(sizeof(*migf), GFP_KERNEL);
-	if (!migf)
+	if (!migf) {
+		dput(vfio_dev_migration);
 		return;
+	}
 	hisi_acc_vdev->debug_migf = migf;
 
 	vfio_hisi_acc = debugfs_create_dir("hisi_acc", vfio_dev_migration);
@@ -1623,6 +1625,8 @@ static void hisi_acc_vfio_debug_init(struct hisi_acc_vf_core_device *hisi_acc_vd
 				    hisi_acc_vf_migf_read);
 	debugfs_create_devm_seqfile(dev, "cmd_state", vfio_hisi_acc,
 				    hisi_acc_vf_debug_cmd);
+
+	dput(vfio_dev_migration);
 }
 
 static void hisi_acc_vf_debugfs_exit(struct hisi_acc_vf_core_device *hisi_acc_vdev)