local-dmabuf: only set dmabuf_supported in the end

We were setting dmabuf_supported to true before calling
IIO_DMABUF_ATTACH_IOCTL that can still fail. Thererefore we would be
wrongly using the DMABUF interface for things like enqueue/dequeue
blocks.

Signed-off-by: Nuno Sa <nuno.sa@analog.com>

local-dmabuf.c

@@ -115,7 +115,6 @@ local_create_dmabuf(struct iio_buffer_pdata *pdata, size_t size, void **data)
 	priv->size = size;
 	priv->buf = pdata;
 	priv->dequeued = true;
-	pdata->dmabuf_supported = true;
 
 	/* The new block is dequeued by default, so enable CPU access */
 	ret = enable_cpu_access(priv, true);
@@ -136,6 +135,8 @@ local_create_dmabuf(struct iio_buffer_pdata *pdata, size_t size, void **data)
 		goto err_data_unmap;
 	}
 
+	pdata->dmabuf_supported = true;
+
 	close(devfd);
 
 	return priv;