drm: remove dev->last_switch

Only ever assigned in the context code for real, with no readers
anywhere. Remove it.
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@gmail.com>

drivers/gpu/drm/drm_context.c

@@ -251,7 +251,6 @@ static int drm_context_switch_complete(struct drm_device *dev,
 				       struct drm_file *file_priv, int new)
 {
 	dev->last_context = new;	/* PRE/POST: This is the _only_ writer. */
-	dev->last_switch = jiffies;
 
 	if (!_DRM_LOCK_IS_HELD(file_priv->master->lock.hw_lock->lock)) {
 		DRM_ERROR("Lock isn't held after context switch\n");

drivers/gpu/drm/drm_fops.c

@@ -79,7 +79,6 @@ static int drm_setup(struct drm_device * dev)
 	dev->interrupt_flag = 0;
 	dev->dma_flag = 0;
 	dev->last_context = 0;
-	dev->last_switch = 0;
 	dev->last_checked = 0;
 	dev->if_version = 0;
 

include/drm/drmP.h

@@ -1135,7 +1135,6 @@ struct drm_device {
 	__volatile__ long dma_flag;	/**< DMA dispatch flag */
 	int last_checked;		/**< Last context checked for DMA */
 	int last_context;		/**< Last current context */
-	unsigned long last_switch;	/**< jiffies at last context switch */
 	/*@} */
 
 	struct work_struct work;