[media] DocBook: update error code in videoc-streamon

Add description of ENOLINK error

Signed-off-by: Helen Mae Koike Fornazier <[e-mail]>
Acked-by: Sakari Ailus <[e-mail]>
Signed-off-by: Mauro Carvalho Chehab <[e-mail]>

Documentation/DocBook/media/v4l/vidioc-streamon.xml

···
 	  </para>
 	</listitem>
       </varlistentry>
+      <varlistentry>
+	<term><errorcode>ENOLINK</errorcode></term>
+	<listitem>
+	  <para>The driver implements Media Controller interface and
+	  the pipeline link configuration is invalid.
+	  </para>
+	</listitem>
+      </varlistentry>
     </variablelist>
   </refsect1>
 </refentry>