ipv4: icmp: use BUG_ON instead of if condition followed by BUG

Use BUG_ON instead of if condition followed by BUG in icmp_timestamp.

This issue was detected with the help of Coccinelle.
Signed-off-by: NGustavo A. R. Silva <garsilva@embeddedor.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/ipv4/icmp.c

@@ -968,8 +968,9 @@ static bool icmp_timestamp(struct sk_buff *skb)
 	 */
 	icmp_param.data.times[1] = inet_current_timestamp();
 	icmp_param.data.times[2] = icmp_param.data.times[1];
-	if (skb_copy_bits(skb, 0, &icmp_param.data.times[0], 4))
-		BUG();
+
+	BUG_ON(skb_copy_bits(skb, 0, &icmp_param.data.times[0], 4));
+
 	icmp_param.data.icmph	   = *icmp_hdr(skb);
 	icmp_param.data.icmph.type = ICMP_TIMESTAMPREPLY;
 	icmp_param.data.icmph.code = 0;