ipconfig: Only bootp paths should reference ic_dev_xid.

It is only tested, and declared, in the bootp code.

So, in ic_dynamic() guard it's setting with IPCONFIG_BOOTP.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/ipv4/ipconfig.c

@@ -1217,10 +1217,10 @@ static int __init ic_dynamic(void)
 	get_random_bytes(&timeout, sizeof(timeout));
 	timeout = CONF_BASE_TIMEOUT + (timeout % (unsigned int) CONF_TIMEOUT_RANDOM);
 	for (;;) {
+#ifdef IPCONFIG_BOOTP
 		/* Track the device we are configuring */
 		ic_dev_xid = d->xid;
 
-#ifdef IPCONFIG_BOOTP
 		if (do_bootp && (d->able & IC_BOOTP))
 			ic_bootp_send_if(d, jiffies - start_jiffies);
 #endif