[IPV4]: Remove bugus goto-s from ip_route_input_slow

Both places look like

        if (err == XXX) 
               goto yyy;
   done:

while both yyy targets look like

        err = XXX;
        goto done;

so this is ok to remove the above if-s.

yyy labels are used in other places and are not removed.

Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>