drm/gm12u320: Use offset-adjusted shadow-plane mappings

For framebuffers with non-zero offset fields, shadow-plane helpers
provide a pointer to the first byte of the contained data. Use it in
gm12u320.
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20210803125928.27780-8-tzimmermann@suse.de

drivers/gpu/drm/tiny/gm12u320.c

@@ -554,7 +554,7 @@ static void gm12u320_pipe_enable(struct drm_simple_display_pipe *pipe,
 	struct drm_shadow_plane_state *shadow_plane_state = to_drm_shadow_plane_state(plane_state);
 
 	gm12u320->fb_update.draw_status_timeout = FIRST_FRAME_TIMEOUT;
-	gm12u320_fb_mark_dirty(plane_state->fb, &shadow_plane_state->map[0], &rect);
+	gm12u320_fb_mark_dirty(plane_state->fb, &shadow_plane_state->data[0], &rect);
 }
 
 static void gm12u320_pipe_disable(struct drm_simple_display_pipe *pipe)
@@ -572,7 +572,7 @@ static void gm12u320_pipe_update(struct drm_simple_display_pipe *pipe,
 	struct drm_rect rect;
 
 	if (drm_atomic_helper_damage_merged(old_state, state, &rect))
-		gm12u320_fb_mark_dirty(state->fb, &shadow_plane_state->map[0], &rect);
+		gm12u320_fb_mark_dirty(state->fb, &shadow_plane_state->data[0], &rect);
 }
 
 static const struct drm_simple_display_pipe_funcs gm12u320_pipe_funcs = {