Revert "Fix in SO_REUSEPORT usage."

This reverts commit 4847e1ba.

src/knot/server/server.c

@@ -118,16 +118,12 @@ static int server_init_iface(iface_t *new_if, conf_iface_t *cfg_if)
 	char addr_str[SOCKADDR_STRLEN] = {0};
 	sockaddr_tostr(&cfg_if->addr, addr_str, sizeof(addr_str));
 
-#if defined(SO_REUSEPORT)
-	/* Each thread binds own socket. */
-	int sock = -1;
-#else
 	/* Create bound UDP socket. */
 	int sock = net_bound_socket(SOCK_DGRAM, &cfg_if->addr);
 	if (sock < 0) {
 		return sock;
 	}
-#endif
+
 	new_if->fd[IO_UDP] = sock;
 
 	/* Create bound TCP socket. */