[media] videodev2: Set vb2_rect's width and height as unsigned

As discussed on the media summit 2013, there is no reason for the width
and height to be signed.

Therefore this patch is an attempt to convert those fields from __s32 to
__u32.

Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Acked-by: Sakari Ailus <sakari.ailus@iki.fi> (documentation and smiapp)
Acked-by: Lad, Prabhakar <prabhakar.csengg@gmail.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>
diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h
index 437f1b0..6ae7bbe 100644
--- a/include/uapi/linux/videodev2.h
+++ b/include/uapi/linux/videodev2.h
@@ -207,8 +207,8 @@
 struct v4l2_rect {
 	__s32   left;
 	__s32   top;
-	__s32   width;
-	__s32   height;
+	__u32   width;
+	__u32   height;
 };
 
 struct v4l2_fract {