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 <fabio.estevam@freescale.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
diff --git a/drivers/char/hw_random/mxc-rnga.c b/drivers/char/hw_random/mxc-rnga.c
index 19a12ac6..6a86b6f 100644
--- a/drivers/char/hw_random/mxc-rnga.c
+++ b/drivers/char/hw_random/mxc-rnga.c
@@ -164,7 +164,9 @@
 		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);