DMAENGINE: ste_dma40: fix clk_get failure path

clk_get returns an ERR_PTR.

Acked-by: Jonas Aaberg <jonas.aberg@stericsson.com>
Signed-off-by: Rabin Vincent <rabin.vincent@stericsson.com>
Signed-off-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

drivers/dma/ste_dma40.c

@@ -2636,7 +2636,7 @@ static struct d40_base * __init d40_hw_detect_init(struct platform_device *pdev)
 	return base;
 
 failure:
-	if (clk) {
+	if (!IS_ERR(clk)) {
 		clk_disable(clk);
 		clk_put(clk);
 	}