If the kzalloc() fails we should return NULL.  All the places that call
alloc_apertures() check for this already.
Signed-off-by: NDan Carpenter <error27@gmail.com>
Acked-by: NJames Simmons <jsimmons@infradead.org>
Acked-by: NMarcin Slusarz <marcin.slusarz@gmail.com>
Signed-off-by: NDave Airlie <airlied@redhat.com>