ipvs: Fix compilation error in ip_vs.h for ip_vs_confirm_conntrack function.

This is to address the following error during the compilation:

  In file included from kernel/sysctl_binary.c:6:
  include/net/ip_vs.h:1406: error: expected identifier or ‘(’ before ‘{’ token
  make[1]: *** [kernel/sysctl_binary.o] Error 1
  make[1]: *** Waiting for unfinished jobs....

That manifests itself when CONFIG_IP_VS_NFCT is undefined in .config file.
Signed-off-by: Krzysztof Wilczynski <krzysztof.wilczynski@linux.com>
Signed-off-by: Simon Horman <horms@verge.net.au>

include/net/ip_vs.h

@@ -1396,7 +1396,7 @@ static inline void ip_vs_update_conntrack(struct sk_buff *skb,
 {
 }
 
-static inline int ip_vs_confirm_conntrack(struct sk_buff *skb);
+static inline int ip_vs_confirm_conntrack(struct sk_buff *skb)
 {
 	return NF_ACCEPT;
 }