dhcp: use the attached sd_device object when generating IAID

Note, previously `use_mac` set with `test_mode`. As `dev`, which is set with
`client->dev`, is not set when running test or fuzzer. Hence, the condition
```
if (udev_available() && !use_mac)
```
is effectively equivalent to
```
if (dev)
```
So, this commit mostly does not change behavior. Except for the following
corner case.

The sd_device object assigned from networkd (that is, Link.dev) never
has ID_RENAMING udev property, as sd_device objects which has the property
are filtered out at `link_check_initialized()` or `manager_udev_process_link()`
in networkd-link.c.

However, sd_device object created in `dhcp_identifier_set_iaid()` in the
previous code may have it. Such situation may (at least, theoretically)
happen when the network interface is renamed after initialized, e.g. by
creating the following spurious .link file:
```
[Match]
OriginalName=eno1
[Link]
Name=lan
```
and then trigger uevent for the network interface while systemd-networkd
calling `dhcp_identifier_set_iaid()`.

1 files changed, 2 insertions, 2 deletions

diff --git a/src/libsystemd-network/dhcp-identifier.h b/src/libsystemd-network/dhcp-identifier.h
index 8acb8c3210..523dfc4a71 100644
--- a/src/libsystemd-network/dhcp-identifier.h
+++ b/src/libsystemd-network/dhcp-identifier.h
@@ -1,6 +1,7 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 #pragma once
 
+#include "sd-device.h"
 #include "sd-id128.h"
 
 #include "ether-addr-util.h"
@@ -66,10 +67,9 @@ int dhcp_identifier_set_duid(
                 struct duid *ret_duid,
                 size_t *ret_len);
 int dhcp_identifier_set_iaid(
-                int ifindex,
+                sd_device *dev,
                 const struct hw_addr_data *hw_addr,
                 bool legacy_unstable_byteorder,
-                bool use_mac,
                 void *ret);
 
 const char *duid_type_to_string(DUIDType t) _const_;