can: mscan: simplify clock enable/disable

All the NULL checks are pointless, clk_*() routines already deal with
NULL just fine.
Signed-off-by: Zhang Changzhong <zhangchangzhong@huawei.com>
Link: https://lore.kernel.org/r/1594972875-27631-1-git-send-email-zhangchangzhong@huawei.comSigned-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

drivers/net/can/mscan/mscan.c

@@ -541,16 +541,12 @@ static int mscan_open(struct net_device *dev)
 	struct mscan_priv *priv = netdev_priv(dev);
 	struct mscan_regs __iomem *regs = priv->reg_base;
 
-	if (priv->clk_ipg) {
 	ret = clk_prepare_enable(priv->clk_ipg);
 	if (ret)
 		goto exit_retcode;
-	}
-	if (priv->clk_can) {
 	ret = clk_prepare_enable(priv->clk_can);
 	if (ret)
 		goto exit_dis_ipg_clock;
-	}
 
 	/* common open */
 	ret = open_candev(dev);
@@ -584,10 +580,8 @@ static int mscan_open(struct net_device *dev)
 	napi_disable(&priv->napi);
 	close_candev(dev);
 exit_dis_can_clock:
-	if (priv->clk_can)
 	clk_disable_unprepare(priv->clk_can);
 exit_dis_ipg_clock:
-	if (priv->clk_ipg)
 	clk_disable_unprepare(priv->clk_ipg);
 exit_retcode:
 	return ret;
@@ -607,9 +601,7 @@ static int mscan_close(struct net_device *dev)
 	close_candev(dev);
 	free_irq(dev->irq, dev);
 
-	if (priv->clk_can)
 	clk_disable_unprepare(priv->clk_can);
-	if (priv->clk_ipg)
 	clk_disable_unprepare(priv->clk_ipg);
 
 	return 0;