[media] V4L: JPEG class documentation corrections

This patch fixes following compilation warning:
Error: no ID for constraint linkend: v4l2-jpeg-chroma-subsampling.

and adds missing JPEG control class at the Table A.58.

Signed-off-by: Sylwester Nawrocki <sylvester.nawrocki@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

Documentation/DocBook/media/v4l/controls.xml

@@ -3978,7 +3978,7 @@ interface and may change in the future.</para>
 	    <entry spanname="id"><constant>V4L2_CID_JPEG_CHROMA_SUBSAMPLING</constant></entry>
 	    <entry>menu</entry>
 	  </row>
-	  <row id="jpeg-chroma-subsampling-control">
+	  <row id="v4l2-jpeg-chroma-subsampling">
 	    <entry spanname="descr">The chroma subsampling factors describe how
 	    each component of an input image is sampled, in respect to maximum
 	    sample rate in each spatial dimension. See <xref linkend="itu-t81"/>,

Documentation/DocBook/media/v4l/vidioc-g-ext-ctrls.xml

@@ -284,6 +284,13 @@ These controls are described in <xref
 	    processing controls. These controls are described in <xref
 	    linkend="image-process-controls" />.</entry>
 	  </row>
+	  <row>
+	    <entry><constant>V4L2_CTRL_CLASS_JPEG</constant></entry>
+	    <entry>0x9d0000</entry>
+	    <entry>The class containing JPEG compression controls.
+These controls are described in <xref
+		linkend="jpeg-controls" />.</entry>
+	  </row>
 	</tbody>
       </tgroup>
     </table>