net: fix icmp_echo_enable_probe sysctl

sysctl_icmp_echo_enable_probe is an u8.

ipv4_net_table entry should use
 .maxlen       = sizeof(u8).
 .proc_handler = proc_dou8vec_minmax,

Fixes: f1b8fa9fa5 ("net: add sysctl for enabling RFC 8335 PROBE messages")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Andreas Roeseler <andreas.a.roeseler@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv4/sysctl_net_ipv4.c

@@ -601,9 +601,9 @@ static struct ctl_table ipv4_net_table[] = {
 	{
 		.procname	= "icmp_echo_enable_probe",
 		.data		= &init_net.ipv4.sysctl_icmp_echo_enable_probe,
-		.maxlen		= sizeof(int),
+		.maxlen		= sizeof(u8),
 		.mode		= 0644,
-		.proc_handler	= proc_dointvec_minmax,
+		.proc_handler	= proc_dou8vec_minmax,
 		.extra1		= SYSCTL_ZERO,
 		.extra2		= SYSCTL_ONE
 	},