Correct documentation regarding PROMISC and ALLMULTI.

The ip util would happily change these flags, it's just not recommended.
Reflect that in the doc.

The behaviour of ifconfig is exactly the same as of ip, delete the note about
it.
Signed-off-by: Tomas Janousek <tjanouse@redhat.com>
Signed-off-by: Stephen Hemminger <shemminger@linux-foundation.org>

doc/ip-cref.tex

@@ -298,9 +298,9 @@ Do not use it, if you do not understand what this operation really does.
 
 \vskip 1mm
 \begin{NB}
-The {\tt ip} utility does not change the \verb|PROMISC| 
-or \verb|ALLMULTI| flags. These flags are considered
-obsolete and should not be changed administratively.
+The \verb|PROMISC| and \verb|ALLMULTI| flags are considered
+obsolete and should not be changed administratively, though
+the {\tt ip} utility will allow that.
 \end{NB}
 
 \paragraph{Warning:} If multiple parameter changes are requested,
@@ -450,13 +450,6 @@ or not implemented (\verb|DEBUG|) or specific to some devices
 (\verb|MASTER|, \verb|AUTOMEDIA| and \verb|PORTSEL|). We do not discuss
 them here.
 \end{NB}
-\begin{NB}
-The values of \verb|PROMISC| and \verb|ALLMULTI| flags
-shown by the \verb|ifconfig| utility and by the \verb|ip| utility
-are {\em different\/}. \verb|ip link ls| shows the true device state,
-while \verb|ifconfig| shows the virtual state which was set with
-\verb|ifconfig| itself.
-\end{NB}
 
 
 The second line contains information on the link layer addresses