drm/qxl: Don't register debugfs for control minors

They're gone since 8a357d10043c ("drm: Nerf DRM_CONTROL nodes").
Spotted while doing a full audit when revieng a similar patch from
Nicolai for radeon.

v2: Drink coffee first aka don't forget the unregister side.

Cc: Dave Airlie <airlied@redhat.com>
Fixes: 8a357d10043c ("drm: Nerf DRM_CONTROL nodes")
Cc: Nicolai Stange <nicstange@gmail.com>
Acked-by: Dave Airlie <airlied@redhat.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20161205072926.12546-1-daniel.vetter@ffwll.ch

drivers/gpu/drm/qxl/qxl_debugfs.c

@@ -122,9 +122,6 @@ int qxl_debugfs_add_files(struct qxl_device *qdev,
 	qdev->debugfs[qdev->debugfs_count].num_files = nfiles;
 	qdev->debugfs_count = i;
 #if defined(CONFIG_DEBUG_FS)
-	drm_debugfs_create_files(files, nfiles,
-				 qdev->ddev->control->debugfs_root,
-				 qdev->ddev->control);
 	drm_debugfs_create_files(files, nfiles,
 				 qdev->ddev->primary->debugfs_root,
 				 qdev->ddev->primary);
@@ -138,9 +135,6 @@ void qxl_debugfs_remove_files(struct qxl_device *qdev)
 	unsigned i;
 
 	for (i = 0; i < qdev->debugfs_count; i++) {
-		drm_debugfs_remove_files(qdev->debugfs[i].files,
-					 qdev->debugfs[i].num_files,
-					 qdev->ddev->control);
 		drm_debugfs_remove_files(qdev->debugfs[i].files,
 					 qdev->debugfs[i].num_files,
 					 qdev->ddev->primary);