drm: Extract drm_is_current_master

Just rolling out a bit of abstraction to be able to clean
up the master logic in the next step.

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Thomas Hellstrom <thellstrom@vmware.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Emil Velikov <emil.l.velikov@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/include/drm/drmP.h b/include/drm/drmP.h
index edbf32e3..8d976ff 100644
--- a/include/drm/drmP.h
+++ b/include/drm/drmP.h
@@ -1014,14 +1014,15 @@
 extern void drm_vblank_pre_modeset(struct drm_device *dev, unsigned int pipe);
 extern void drm_vblank_post_modeset(struct drm_device *dev, unsigned int pipe);
 
-				/* Stub support (drm_stub.h) */
-extern struct drm_master *drm_master_get(struct drm_master *master);
-extern void drm_master_put(struct drm_master **master);
+/* drm_auth.c */
+struct drm_master *drm_master_get(struct drm_master *master);
+void drm_master_put(struct drm_master **master);
+bool drm_is_current_master(struct drm_file *fpriv);
 
-extern void drm_put_dev(struct drm_device *dev);
-extern void drm_unplug_dev(struct drm_device *dev);
+/* drm_drv.c */
+void drm_put_dev(struct drm_device *dev);
+void drm_unplug_dev(struct drm_device *dev);
 extern unsigned int drm_debug;
-extern bool drm_atomic;
 
 				/* Debugfs support */
 #if defined(CONFIG_DEBUG_FS)