tests/9pfs: Turn fs_mkdir() into a helper

fs_mkdir() isn't a top level test function and thus shouldn't take
the "void *obj, void *data, QGuestAllocator *t_alloc" arguments.
Turn it into a helper to be used by test functions.

Signed-off-by: Greg Kurz <groug@kaod.org>
Message-Id: <160321018148.266767.15959608711038504029.stgit@bahia.lan>
Signed-off-by: Christian Schoenebeck <qemu_oss@crudebyte.com>

tests/qtest/virtio-9p-test.c

@@ -972,11 +972,8 @@ static void fs_flush_ignored(void *obj, void *data, QGuestAllocator *t_alloc)
     g_free(wnames[0]);
 }
 
-static void fs_mkdir(void *obj, void *data, QGuestAllocator *t_alloc,
-                     const char *path, const char *cname)
+static void do_mkdir(QVirtio9P *v9p, const char *path, const char *cname)
 {
-    QVirtio9P *v9p = obj;
-    alloc = t_alloc;
     char **wnames;
     char *const name = g_strdup(cname);
     P9Req *req;
@@ -1031,7 +1028,7 @@ static void fs_create_dir(void *obj, void *data, QGuestAllocator *t_alloc)
     g_assert(root_path != NULL);
 
     do_attach(v9p);
-    fs_mkdir(v9p, data, t_alloc, "/", "01");
+    do_mkdir(v9p, "/", "01");
 
     /* check if created directory really exists now ... */
     g_assert(stat(new_dir, &st) == 0);