[NETLINK]: cleanup unused macro in net/netlink/af_netlink.c

1 line removal, of unused macro.
ran 'egrep -r' from linux-2.6.16/ for Nprintk and
didn't see it anywhere else but here, in #define...

Signed-off-by: Soyoung Park <speattle@yahoo.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/netlink/af_netlink.c

@@ -61,7 +61,6 @@
 #include <net/scm.h>
 #include <net/netlink.h>
 
-#define Nprintk(a...)
 #define NLGRPSZ(x)	(ALIGN(x, sizeof(unsigned long) * 8) / 8)
 
 struct netlink_sock {