ipv4: optimize fib_compute_spec_dst call in ip_options_echo

Move fib_compute_spec_dst at the only place where it
is needed.

Signed-off-by: Julian Anastasov <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

net/ipv4/ip_options.c

···
 	unsigned char *sptr, *dptr;
 	int soffset, doffset;
 	int	optlen;
-	__be32	daddr;
 
 	memset(dopt, 0, sizeof(struct ip_options));
 
···
 
 	sptr = skb_network_header(skb);
 	dptr = dopt->__data;
-
-	daddr = fib_compute_spec_dst(skb);
 
 	if (sopt->rr) {
 		optlen  = sptr[sopt->rr+1];
···
 				doffset -= 4;
 		}
 		if (doffset > 3) {
+			__be32 daddr = fib_compute_spec_dst(skb);
+
 			memcpy(&start[doffset-1], &daddr, 4);
 			dopt->faddr = faddr;
 			dptr[0] = start[0];