[IPV4] fib_trie: Add credits.

Signed-off-by: NRobert Olsson <robert.olsson@its.uu.se>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/ipv4/fib_trie.c

@@ -41,6 +41,13 @@
  *		modify it under the terms of the GNU General Public License
  *		as published by the Free Software Foundation; either version
  *		2 of the License, or (at your option) any later version.
+ *
+ * Substantial contributions to this work comes from:
+ *
+ *		David S. Miller, <davem@davemloft.net>
+ *		Stephen Hemminger <shemminger@osdl.org>
+ *		Paul E. McKenney <paulmck@us.ibm.com>
+ *		Patrick McHardy <kaber@trash.net>
  */
 
 #define VERSION "0.404"