drm/simpledrm: Use offset-adjusted shadow-plane mapping

For framebuffers with non-zero offset fields, shadow-plane helpers
provide a pointer to the first byte of the contained data. Use it in
simpledrm.
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20210803125928.27780-9-tzimmermann@suse.de

drivers/gpu/drm/tiny/simpledrm.c

@@ -639,7 +639,7 @@ simpledrm_simple_display_pipe_enable(struct drm_simple_display_pipe *pipe,
 	struct simpledrm_device *sdev = simpledrm_device_of_dev(pipe->crtc.dev);
 	struct drm_shadow_plane_state *shadow_plane_state = to_drm_shadow_plane_state(plane_state);
 	struct drm_framebuffer *fb = plane_state->fb;
-	void *vmap = shadow_plane_state->map[0].vaddr; /* TODO: Use mapping abstraction properly */
+	void *vmap = shadow_plane_state->data[0].vaddr; /* TODO: Use mapping abstraction */
 	struct drm_device *dev = &sdev->dev;
 	int idx;
 
@@ -677,7 +677,7 @@ simpledrm_simple_display_pipe_update(struct drm_simple_display_pipe *pipe,
 	struct simpledrm_device *sdev = simpledrm_device_of_dev(pipe->crtc.dev);
 	struct drm_plane_state *plane_state = pipe->plane.state;
 	struct drm_shadow_plane_state *shadow_plane_state = to_drm_shadow_plane_state(plane_state);
-	void *vmap = shadow_plane_state->map[0].vaddr; /* TODO: Use mapping abstraction properly */
+	void *vmap = shadow_plane_state->data[0].vaddr; /* TODO: Use mapping abstraction */
 	struct drm_framebuffer *fb = plane_state->fb;
 	struct drm_device *dev = &sdev->dev;
 	struct drm_rect clip;