[IPV4]: Remove no longer available URL.

This patch solves Bugzilla #2445 by removing a no longer available URL 
from the help text for NET_IPIP.

Noted by Nils Hammar <m4341@bedug.com>.
Signed-off-by: Adrian Bunk <bunk@fs.tum.de>
Signed-off-by: David S. Miller <davem@redhat.com>

net/ipv4/Kconfig

@@ -196,8 +196,7 @@ config NET_IPIP
 	  can be useful if you want to make your (or some other) machine
 	  appear on a different network than it physically is, or to use
 	  mobile-IP facilities (allowing laptops to seamlessly move between
-	  networks without changing their IP addresses; check out
-	  <http://anchor.cs.binghamton.edu/~mobileip/LJ/index.html>).
+	  networks without changing their IP addresses).
 
 	  Saying Y to this option will produce two modules ( = code which can
 	  be inserted in and removed from the running kernel whenever you