drm/lease: fix WARNING in idr_destroy

drm_lease_create takes ownership of leases. And leases will be released
by drm_master_put.

drm_master_put
    ->drm_master_destroy
            ->idr_destroy

So we needn't call idr_destroy again.

Reported-and-tested-by: syzbot+05835159fe322770fe3d@syzkaller.appspotmail.com
Signed-off-by: Qiujun Huang <hqjagain@gmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/1584518030-4173-1-git-send-email-hqjagain@gmail.com

drivers/gpu/drm/drm_lease.c

@@ -542,10 +542,12 @@ int drm_mode_create_lease_ioctl(struct drm_device *dev,
 	}
 
 	DRM_DEBUG_LEASE("Creating lease\n");
+	/* lessee will take the ownership of leases */
 	lessee = drm_lease_create(lessor, &leases);
 
 	if (IS_ERR(lessee)) {
 		ret = PTR_ERR(lessee);
+		idr_destroy(&leases);
 		goto out_leases;
 	}
 
@@ -580,7 +582,6 @@ int drm_mode_create_lease_ioctl(struct drm_device *dev,
 
 out_leases:
 	put_unused_fd(fd);
-	idr_destroy(&leases);
 
 	DRM_DEBUG_LEASE("drm_mode_create_lease_ioctl failed: %d\n", ret);
 	return ret;