[NETFILTER]: conntrack: get rid of sparse warnings

Teach sparse about locking here, and fix signed/unsigned warnings.

Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/netfilter/nf_conntrack_irc.c b/net/netfilter/nf_conntrack_irc.c
index dfaed4b..c336b07 100644
--- a/net/netfilter/nf_conntrack_irc.c
+++ b/net/netfilter/nf_conntrack_irc.c
@@ -23,7 +23,7 @@
 
 #define MAX_PORTS 8
 static unsigned short ports[MAX_PORTS];
-static int ports_c;
+static unsigned int ports_c;
 static unsigned int max_dcc_channels = 8;
 static unsigned int dcc_timeout __read_mostly = 300;
 /* This is slow, but it's simple. --RR */