nf_conntrack.h: fix up fallout from implicit moduleparam.h presence

The implicit presence of module.h everywhere meant that this header
also was getting moduleparam.h which defines struct kernel_param.

Since it only needs to know that kernel_param is a struct, call that
out instead of adding an include of moduleparam.h -- to get rid of this:

include/net/netfilter/nf_conntrack.h:316: warning: 'struct kernel_param' declared inside parameter list
include/net/netfilter/nf_conntrack.h:316: warning: its scope is only this definition or declaration, which is probably not what you want
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>

include/net/netfilter/nf_conntrack.h

@@ -313,6 +313,8 @@ static inline bool nf_is_loopback_packet(const struct sk_buff *skb)
 	return skb->dev && skb->skb_iif && skb->dev->flags & IFF_LOOPBACK;
 }
 
+struct kernel_param;
+
 extern int nf_conntrack_set_hashsize(const char *val, struct kernel_param *kp);
 extern unsigned int nf_conntrack_htable_size;
 extern unsigned int nf_conntrack_max;