net: Use id_generate() in the network subsystem, too

We already got a global function called id_generate() to create unique
IDs within QEMU. Let's use it in the network subsytem, too, instead of
inventing our own ID scheme here.

Signed-off-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20210215090225.1046239-1-thuth@redhat.com>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>

include/qemu/id.h

@@ -5,6 +5,7 @@ typedef enum IdSubSystems {
     ID_QDEV,
     ID_BLOCK,
     ID_CHR,
+    ID_NET,
     ID_MAX      /* last element, used as array size */
 } IdSubSystems;