netfilter: Remove the now superfluous sentinel elements from ctl_table array

This commit comes at the tail end of a greater effort to remove the
empty elements at the end of the ctl_table arrays (sentinels) which will
reduce the overall build time size of the kernel and run time memory
bloat by ~64 bytes per sentinel (further information Link :
https://lore.kernel.org/all/[e-mail]/)

* Remove sentinel elements from ctl_table structs
* Remove instances where an array element is zeroed out to make it look
like a sentinel. This is not longer needed and is safe after commit
c899710fe7f9 ("networking: Update to register_net_sysctl_sz") added
the array size to the ctl_table registration
* Remove the need for having __NF_SYSCTL_CT_LAST_SYSCTL as the
sysctl array size is now in NF_SYSCTL_CT_LAST_SYSCTL
* Remove extra element in ctl_table arrays declarations

Acked-by: Kees Cook <[e-mail]> # loadpin & yama
Signed-off-by: Joel Granados <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

net/bridge/br_netfilter_hooks.c

···
 		.mode		= 0644,
 		.proc_handler	= brnf_sysctl_call_tables,
 	},
-	{ }
 };
 
 static inline void br_netfilter_sysctl_default(struct brnf_net *brnf)

net/ipv6/netfilter/nf_conntrack_reasm.c

···
 		.mode		= 0644,
 		.proc_handler	= proc_doulongvec_minmax,
 	},
-	{ }
 };
 
 static int nf_ct_frag6_sysctl_register(struct net *net)

net/netfilter/ipvs/ip_vs_ctl.c

···
 		.proc_handler	= proc_dointvec,
 	},
 #endif
-	{ }
 };
 
 #endif
···
 			return -ENOMEM;
 
 		/* Don't export sysctls to unprivileged users */
-		if (net->user_ns != &init_user_ns) {
-			tbl[0].procname = NULL;
+		if (net->user_ns != &init_user_ns)
 			ctl_table_size = 0;
-		}
 	} else
 		tbl = vs_vars;
 	/* Initialize sysctl defaults */

net/netfilter/ipvs/ip_vs_lblc.c

···
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_jiffies,
 	},
-	{ }
 };
 #endif
 
···
 			return -ENOMEM;
 
 		/* Don't export sysctls to unprivileged users */
-		if (net->user_ns != &init_user_ns) {
-			ipvs->lblc_ctl_table[0].procname = NULL;
+		if (net->user_ns != &init_user_ns)
 			vars_table_size = 0;
-		}
 
 	} else
 		ipvs->lblc_ctl_table = vs_vars_table;

net/netfilter/ipvs/ip_vs_lblcr.c

···
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_jiffies,
 	},
-	{ }
 };
 #endif
 
···
 			return -ENOMEM;
 
 		/* Don't export sysctls to unprivileged users */
-		if (net->user_ns != &init_user_ns) {
-			ipvs->lblcr_ctl_table[0].procname = NULL;
+		if (net->user_ns != &init_user_ns)
 			vars_table_size = 0;
-		}
 	} else
 		ipvs->lblcr_ctl_table = vs_vars_table;
 	ipvs->sysctl_lblcr_expiration = DEFAULT_EXPIRATION;

net/netfilter/nf_conntrack_standalone.c

···
 	NF_SYSCTL_CT_LWTUNNEL,
 #endif
 
-	__NF_SYSCTL_CT_LAST_SYSCTL,
+	NF_SYSCTL_CT_LAST_SYSCTL,
 };
-
-#define NF_SYSCTL_CT_LAST_SYSCTL (__NF_SYSCTL_CT_LAST_SYSCTL + 1)
 
 static struct ctl_table nf_ct_sysctl_table[] = {
 	[NF_SYSCTL_CT_MAX] = {
···
 		.proc_handler	= nf_hooks_lwtunnel_sysctl_handler,
 	},
 #endif
-	{}
 };
 
 static struct ctl_table nf_ct_netfilter_table[] = {
···
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec,
 	},
-	{ }
 };
 
 static void nf_conntrack_standalone_init_tcp_sysctl(struct net *net,

net/netfilter/nf_log.c

···
 
 #ifdef CONFIG_SYSCTL
 static char nf_log_sysctl_fnames[NFPROTO_NUMPROTO-NFPROTO_UNSPEC][3];
-static struct ctl_table nf_log_sysctl_table[NFPROTO_NUMPROTO+1];
+static struct ctl_table nf_log_sysctl_table[NFPROTO_NUMPROTO];
 static struct ctl_table_header *nf_log_sysctl_fhdr;
 
 static struct ctl_table nf_log_sysctl_ftable[] = {
···
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec,
 	},
-	{ }
 };
 
 static int nf_log_proc_dostring(struct ctl_table *table, int write,