net: Mention net-next status web page in netdev-FAQ.txt

According to
  https://www.mail-archive.com/netdev@vger.kernel.org/msg177411.html
there is a status page available at
  http://vger.kernel.org/~davem/net-next.html
to obtain the current status of the net-next tree.  Let's add this
information to the netdev FAQ.

Signed-off-by: Harald Welte <laforge@gnumonks.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

Documentation/networking/netdev-FAQ.txt

@@ -64,7 +64,10 @@ A: To understand this, you need to know a bit of background information
 
    If you aren't subscribed to netdev and/or are simply unsure if net-next
    has re-opened yet, simply check the net-next git repository link above for
-   any new networking-related commits.
+   any new networking-related commits.  You may also check the following
+   website for the current status:
+
+        http://vger.kernel.org/~davem/net-next.html
 
    The "net" tree continues to collect fixes for the vX.Y content, and
    is fed back to Linus at regular (~weekly) intervals.  Meaning that the