V4L/DVB: v4l videobuf: remove unused mmap callback

The mmap callback in struct videobuf_qtype_ops is never used.
Remove.

Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

include/media/videobuf-core.h

@@ -132,10 +132,6 @@ struct videobuf_qtype_ops {
 	int (*iolock)		(struct videobuf_queue *q,
 				 struct videobuf_buffer *vb,
 				 struct v4l2_framebuffer *fbuf);
-	int (*mmap)		(struct videobuf_queue *q,
-				 unsigned int *count,
-				 unsigned int *size,
-				 enum v4l2_memory memory);
 	int (*sync)		(struct videobuf_queue *q,
 				 struct videobuf_buffer *buf);
 	int (*video_copy_to_user)(struct videobuf_queue *q,