hwrng: mxc-rnga - Check the return value from clk_prepare_enable()

clk_prepare_enable() may fail, so let's check its return value and propagate it
in the case of error.

Signed-off-by: Fabio Estevam <[e-mail]>
Signed-off-by: Herbert Xu <[e-mail]>

drivers/char/hw_random/mxc-rnga.c

···
 		goto out;
 	}
 
-	clk_prepare_enable(mxc_rng->clk);
+	err = clk_prepare_enable(mxc_rng->clk);
+	if (err)
+		goto out;
 
 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	mxc_rng->mem = devm_ioremap_resource(&pdev->dev, res);