vrend: Don't try to deref gbm if it was not initialized

minigbm allocations being enabled does not imply that GBM is also
initialized, e.g. if the renderer uses a GLX context, so don't try
to dereference gbm.

Signed-off-by: Gert Wollny <gert.wollny@collabora.com>
Reviewed-by: John Bates <jbates@chromium.org>
1 file changed