[media] v4l: Fix media_entity_to_video_device macro argument name

The name 'entity' is used twice in the macro body, once as the macro
argument, and once as a structure field name. This breaks compilation if
the macro is called with its argument not named 'entity'.

Fix this by renaming the macro argument '__e'. This should avoid
namespace clashes.
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

include/media/v4l2-dev.h

@@ -128,8 +128,8 @@ struct video_device
 	struct mutex *lock;
 };
 
-#define media_entity_to_video_device(entity) \
-	container_of(entity, struct video_device, entity)
+#define media_entity_to_video_device(__e) \
+	container_of(__e, struct video_device, entity)
 /* dev to video-device */
 #define to_video_device(cd) container_of(cd, struct video_device, dev)