dmaengine: tegra-apb: Add missing of_dma_controller_free

The DMA controller shall be released on driver's removal.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Acked-by: Jon Hunter <jonathanh@nvidia.com>
Link: https://lore.kernel.org/r/20200209163356.6439-15-digetx@gmail.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

drivers/dma/tegra20-apb-dma.c

@@ -1573,6 +1573,7 @@ static int tegra_dma_remove(struct platform_device *pdev)
 {
 	struct tegra_dma *tdma = platform_get_drvdata(pdev);
 
+	of_dma_controller_free(pdev->dev.of_node);
 	dma_async_device_unregister(&tdma->dma_dev);
 	pm_runtime_disable(&pdev->dev);
 	clk_unprepare(tdma->dma_clk);