drm/vc4: vc4_plane_duplicate_state() can be static

Signed-off-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Eric Anholt <eric@anholt.net>

drivers/gpu/drm/vc4/vc4_plane.c

@@ -70,7 +70,7 @@ static bool plane_enabled(struct drm_plane_state *state)
 	return state->fb && state->crtc;
 }
 
-struct drm_plane_state *vc4_plane_duplicate_state(struct drm_plane *plane)
+static struct drm_plane_state *vc4_plane_duplicate_state(struct drm_plane *plane)
 {
 	struct vc4_plane_state *vc4_state;
 
@@ -97,8 +97,8 @@ struct drm_plane_state *vc4_plane_duplicate_state(struct drm_plane *plane)
 	return &vc4_state->base;
 }
 
-void vc4_plane_destroy_state(struct drm_plane *plane,
-			     struct drm_plane_state *state)
+static void vc4_plane_destroy_state(struct drm_plane *plane,
+				    struct drm_plane_state *state)
 {
 	struct vc4_plane_state *vc4_state = to_vc4_plane_state(state);
 
@@ -108,7 +108,7 @@ void vc4_plane_destroy_state(struct drm_plane *plane,
 }
 
 /* Called during init to allocate the plane's atomic state. */
-void vc4_plane_reset(struct drm_plane *plane)
+static void vc4_plane_reset(struct drm_plane *plane)
 {
 	struct vc4_plane_state *vc4_state;