[IPV4] fib_trie: Add statistics.

The FIB TRIE code has a bunch of statistics, but the code is hidden
behind an ifdef that was never implemented. Since it was dead code, it
was broken as well.

This patch fixes that by making it a config option.

Signed-off-by: Stephen Hemminger <stephen.hemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/Kconfig b/net/ipv4/Kconfig
index 9f9fd2c..24e2b72 100644
--- a/net/ipv4/Kconfig
+++ b/net/ipv4/Kconfig
@@ -85,6 +85,13 @@
 config IP_FIB_HASH
 	def_bool ASK_IP_FIB_HASH || !IP_ADVANCED_ROUTER
 
+config IP_FIB_TRIE_STATS
+	bool "FIB TRIE statistics"
+	depends on IP_FIB_TRIE
+	---help---
+	  Keep track of statistics on structure of FIB TRIE table.
+	  Useful for testing and measuring TRIE performance.
+
 config IP_MULTIPLE_TABLES
 	bool "IP: policy routing"
 	depends on IP_ADVANCED_ROUTER