drm: rip out dev->last_checked

Only ever re-cleared in drm_setup, otherwise completely unused.
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@gmail.com>

drivers/gpu/drm/drm_fops.c

@@ -77,7 +77,6 @@ static int drm_setup(struct drm_device * dev)
 
 	dev->context_flag = 0;
 	dev->last_context = 0;
-	dev->last_checked = 0;
 	dev->if_version = 0;
 
 	dev->buf_async = NULL;

include/drm/drmP.h

@@ -1131,7 +1131,6 @@ struct drm_device {
 	/*@{ */
 	int irq_enabled;		/**< True if irq handler is enabled */
 	__volatile__ long context_flag;	/**< Context swapping flag */
-	int last_checked;		/**< Last context checked for DMA */
 	int last_context;		/**< Last current context */
 	/*@} */