[media] v4l2_plane_pix_format: use __u32 bytesperline instead of __u16

While running v4l2-compliance tests on vivid I suddenly got errors due to
a call to vmalloc_user with size 0 from vb2.

Digging deeper into the cause I discovered that this was due to the fact that
struct v4l2_plane_pix_format defines bytesperline as a __u16 instead of a __u32.

The test I was running selected a format of 4 * 4096 by 4 * 2048 with a 32
bit pixelformat.

So bytesperline was 4 * 4 * 4096 = 65536, which becomes 0 in a __u16. And
bytesperline * height is suddenly 0 as well. While the vivid driver may be
a virtual driver, it is to be expected that this limit will be hit for real
hardware as well in the near future: 8k deep-color video will already reach
it.

The solution is to change the type to __u32. The only drivers besides vivid
that use the multiplanar API are little-endian ARM and SH platforms (exynos,
ti-vpe, vsp1), so this is safe.
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>

Documentation/DocBook/media/v4l/pixfmt.xml

@@ -182,14 +182,14 @@ see <xref linkend="colorspaces" />.</entry>
           </entry>
         </row>
         <row>
-          <entry>__u16</entry>
+          <entry>__u32</entry>
           <entry><structfield>bytesperline</structfield></entry>
           <entry>Distance in bytes between the leftmost pixels in two adjacent
             lines. See &v4l2-pix-format;.</entry>
         </row>
         <row>
           <entry>__u16</entry>
-          <entry><structfield>reserved[7]</structfield></entry>
+          <entry><structfield>reserved[6]</structfield></entry>
           <entry>Reserved for future extensions. Should be zeroed by the
            application.</entry>
         </row>

drivers/media/platform/s5p-tv/mixer_video.c

@@ -287,7 +287,7 @@ static void mxr_mplane_fill(struct v4l2_plane_pix_format *planes,
 		u32 bl_width = divup(width, blk->width);
 		u32 bl_height = divup(height, blk->height);
 		u32 sizeimage = bl_width * bl_height * blk->size;
-		u16 bytesperline = bl_width * blk->size / blk->height;
+		u32 bytesperline = bl_width * blk->size / blk->height;
 
 		plane->sizeimage += sizeimage;
 		plane->bytesperline = max(plane->bytesperline, bytesperline);

include/uapi/linux/videodev2.h

@@ -1842,8 +1842,8 @@ struct v4l2_mpeg_vbi_fmt_ivtv {
  */
 struct v4l2_plane_pix_format {
 	__u32		sizeimage;
-	__u16		bytesperline;
-	__u16		reserved[7];
+	__u32		bytesperline;
+	__u16		reserved[6];
 } __attribute__ ((packed));
 
 /**