cfgt: documment that pv module has to be loaded in order to work

src/modules/cfgt/doc/cfgt_admin.xml

@@ -35,7 +35,7 @@
 			<itemizedlist>
 			<listitem>
 			<para>
-				<emphasis>None</emphasis>.
+				<emphasis>pv</emphasis>.
 			</para>
 			</listitem>
 			</itemizedlist>