mtd: nand: pxa3xx: Check for clk_prepare_enable() return value

clk_prepare_enable() can fail due to unknown reason.
Add a check for this and return the error code if it fails.

Signed-off-by: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

drivers/mtd/nand/pxa3xx_nand.c

@@ -1072,7 +1072,9 @@ static int alloc_nand_resource(struct platform_device *pdev)
 		dev_err(&pdev->dev, "failed to get nand clock\n");
 		return PTR_ERR(info->clk);
 	}
-	clk_prepare_enable(info->clk);
+	ret = clk_prepare_enable(info->clk);
+	if (ret < 0)
+		return ret;
 
 	/*
 	 * This is a dirty hack to make this driver work from devicetree