gbm/dri: Fix leaking bo memory on failure path

In gbm_dri_bo_create, when modifiers are requested but not supported, do
not return NULL immediately, but first go to cleanup section to free
already allocated buffer object.

Fixes: cb9ae4273d ("dri: add loader_dri_create_image helper")
Signed-off-by: Heinrich Fink <hfink@snap.com>
Reviewed-by: Daniel Stone <daniels@collabora.com>
Reviewed-by: Simon Ser <contact@emersion.fr>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/11844>

src/gbm/backends/dri/gbm_dri.c

@@ -1196,7 +1196,7 @@ gbm_dri_bo_create(struct gbm_device *gbm,
    if (modifiers && (dri->image->base.version < 14 ||
        !dri->image->createImageWithModifiers)) {
       errno = ENOSYS;
-      return NULL;
+      goto failed;
    }
 
    bo->image = loader_dri_create_image(dri->screen, dri->image, width, height,