staging: mt7621-dma: Fix a resource leak in an error handling path

If an error occurs after calling 'mtk_hsdma_init()', it must be undone by
a corresponding call to 'mtk_hsdma_uninit()' as already done in the
remove function.

Fixes: 0853c7a5 ("staging: mt7621-dma: ralink: add rt2880 dma engine")
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20201213153513.138723-1-christophe.jaillet@wanadoo.frSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/mt7621-dma/mtk-hsdma.c

@@ -712,7 +712,7 @@ static int mtk_hsdma_probe(struct platform_device *pdev)
 	ret = dma_async_device_register(dd);
 	if (ret) {
 		dev_err(&pdev->dev, "failed to register dma device\n");
-		return ret;
+		goto err_uninit_hsdma;
 	}
 
 	ret = of_dma_controller_register(pdev->dev.of_node,
@@ -728,6 +728,8 @@ static int mtk_hsdma_probe(struct platform_device *pdev)
 
 err_unregister:
 	dma_async_device_unregister(dd);
+err_uninit_hsdma:
+	mtk_hsdma_uninit(hsdma);
 	return ret;
 }