[media] v4l: Add VIDIOC_LOG_STATUS support for sub-device nodes

The VIDIOC_LOG_STATUS ioctl allows to dump the current status of a driver
to the kernel log. Currently this ioctl is only available at video device
nodes and the subdevs rely on the host driver to expose their core.log_status
operation to user space.

This patch adds VIDIOC_LOG_STATUS support at the sub-device nodes,
for standalone subdevs that expose their own /dev entry.

Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/video/v4l2-subdev.c

@@ -193,6 +193,10 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg)
 		return v4l2_subdev_call(sd, core, s_register, p);
 	}
 #endif
+
+	case VIDIOC_LOG_STATUS:
+		return v4l2_subdev_call(sd, core, log_status);
+
 #if defined(CONFIG_VIDEO_V4L2_SUBDEV_API)
 	case VIDIOC_SUBDEV_G_FMT: {
 		struct v4l2_subdev_format *format = arg;