fbdev: sh_mobile_hdmi: implement locking

The SH-Mobile HDMI driver runs in several contexts: ISR, delayed work-queue,
task context, when called from the sh_mobile_lcdc framebuffer driver. This
creates ample race possibilities. Even though most these races are purely
theoretical, it is better to close them. To trace fb_info validity we install a
notification callback in the HDMI driver, and the only way for it to get to
driver internal data is by using struct sh_mobile_lcdc_chan, therefore it had
to be extracted into a separate common header.

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
diff --git a/include/video/sh_mobile_lcdc.h b/include/video/sh_mobile_lcdc.h
index 19c69d7..daabae5 100644
--- a/include/video/sh_mobile_lcdc.h
+++ b/include/video/sh_mobile_lcdc.h
@@ -49,7 +49,9 @@
 	unsigned long (*read_data)(void *handle);
 };
 
+struct module;
 struct sh_mobile_lcdc_board_cfg {
+	struct module *owner;
 	void *board_data;
 	int (*setup_sys)(void *board_data, void *sys_ops_handle,
 			 struct sh_mobile_lcdc_sys_bus_ops *sys_ops);