hw/cxl: Fix memory leak in error paths

Use g_autofree to free the CXLFixedWindow structure if an
error occurs in configuration before we have added to
the list (via g_steal_pointer())

Fix Coverity CID: 1488872

Reported-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Message-Id: <20220808122051.14822-2-Jonathan.Cameron@huawei.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

hw/cxl/cxl-host.c

@@ -26,7 +26,7 @@ static void cxl_fixed_memory_window_config(CXLState *cxl_state,
                                            CXLFixedMemoryWindowOptions *object,
                                            Error **errp)
 {
-    CXLFixedWindow *fw = g_malloc0(sizeof(*fw));
+    g_autofree CXLFixedWindow *fw = g_malloc0(sizeof(*fw));
     strList *target;
     int i;
 
@@ -64,7 +64,8 @@ static void cxl_fixed_memory_window_config(CXLState *cxl_state,
         fw->enc_int_gran = 0;
     }
 
-    cxl_state->fixed_windows = g_list_append(cxl_state->fixed_windows, fw);
+    cxl_state->fixed_windows = g_list_append(cxl_state->fixed_windows,
+                                             g_steal_pointer(&fw));
 
     return;
 }