[media] v4l2-ioctl: Add a default value for kernel version

Most drivers don't increase kernel versions as newer features are added or
bug fixes are solved. So, vidioc_querycap returned value for cap->version is
meaningless. Instead of keeping this situation forever, let's add a default
value matching the current Linux version.

Drivers that want to keep their own version control can still do it, as they
can override the default value for cap->version.
Acked-by: NHans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/video/v4l2-ioctl.c

@@ -16,6 +16,7 @@
 #include <linux/slab.h>
 #include <linux/types.h>
 #include <linux/kernel.h>
+#include <linux/version.h>
 
 #include <linux/videodev2.h>
 
@@ -605,6 +606,7 @@ static long __video_do_ioctl(struct file *file,
 		if (!ops->vidioc_querycap)
 			break;
 
+		cap->version = LINUX_VERSION_CODE;
 		ret = ops->vidioc_querycap(file, fh, cap);
 		if (!ret)
 			dbgarg(cmd, "driver=%s, card=%s, bus=%s, "