V4L/DVB (11293): uvcvideo: Add zero fill for VIDIOC_ENUM_FMT

When enumerating formats with VIDIOC_ENUM_FMT the uvcvideo driver does not
fill the reserved fields of the struct v4l2_fmtdesc with zeros as required by
V4L2 API revision 0.24 [1]. Add the missing initializations.

The patch was tested with v4l-test 0.10 [2] with CNF7129 webcam found on EeePC
901.

References:
[1] V4L2 API specification, revision 0.24
    http://v4l2spec.bytesex.org/spec/r8367.htm

[2] v4l-test: Test environment for Video For Linux Two API
    http://v4l-test.sourceforge.net/Signed-off-by: Márton Németh <nm127@freemail.hu>
Signed-off-by: Laurent Pinchart <laurent.pinchart@skynet.be>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/video/uvc/uvc_v4l2.c

@@ -673,11 +673,17 @@ static long uvc_v4l2_do_ioctl(struct file *file, unsigned int cmd, void *arg)
 	{
 		struct v4l2_fmtdesc *fmt = arg;
 		struct uvc_format *format;
+		enum v4l2_buf_type type = fmt->type;
+		__u32 index = fmt->index;
 
 		if (fmt->type != video->streaming->type ||
 		    fmt->index >= video->streaming->nformats)
 			return -EINVAL;
 
+		memset(fmt, 0, sizeof(*fmt));
+		fmt->index = index;
+		fmt->type = type;
+
 		format = &video->streaming->format[fmt->index];
 		fmt->flags = 0;
 		if (format->flags & UVC_FMT_FLAG_COMPRESSED)