crypto: omap-aes - don't treat NULL clk as an error

clk_get() returns a struct clk cookie to the driver and some platforms
may return NULL if they only support a single clock.  clk_get() has only
failed if it returns a ERR_PTR() encoded pointer.
Signed-off-by: Jamie Iles <jamie@jamieiles.com>
Reviewed-and-tested-by: Tobias Karnat <tobias.karnat@googlemail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

drivers/crypto/omap-aes.c

@@ -839,9 +839,9 @@ static int omap_aes_probe(struct platform_device *pdev)
 
 	/* Initializing the clock */
 	dd->iclk = clk_get(dev, "ick");
-	if (!dd->iclk) {
+	if (IS_ERR(dd->iclk)) {
 		dev_err(dev, "clock intialization failed.\n");
-		err = -ENODEV;
+		err = PTR_ERR(dd->iclk);
 		goto err_res;
 	}