can: flexcan: factor out transceiver {en,dis}able into seperate functions

This patch moves the transceiver enable and disable into seperate functions,
where the NULL pointer check is hidden.

Cc: linux-stable <stable@vger.kernel.org>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

drivers/net/can/flexcan.c

@@ -264,6 +264,22 @@ static inline void flexcan_write(u32 val, void __iomem *addr)
 }
 #endif
 
+static inline int flexcan_transceiver_enable(const struct flexcan_priv *priv)
+{
+	if (!priv->reg_xceiver)
+		return 0;
+
+	return regulator_enable(priv->reg_xceiver);
+}
+
+static inline int flexcan_transceiver_disable(const struct flexcan_priv *priv)
+{
+	if (!priv->reg_xceiver)
+		return 0;
+
+	return regulator_disable(priv->reg_xceiver);
+}
+
 static inline int flexcan_has_and_handle_berr(const struct flexcan_priv *priv,
 					      u32 reg_esr)
 {
@@ -808,11 +824,9 @@ static int flexcan_chip_start(struct net_device *dev)
 	if (priv->devtype_data->features & FLEXCAN_HAS_V10_FEATURES)
 		flexcan_write(0x0, &regs->rxfgmask);
 
-	if (priv->reg_xceiver)	{
-		err = regulator_enable(priv->reg_xceiver);
+	err = flexcan_transceiver_enable(priv);
 	if (err)
 		goto out;
-	}
 
 	/* synchronize with the can bus */
 	reg_mcr = flexcan_read(&regs->mcr);
@@ -857,8 +871,7 @@ static void flexcan_chip_stop(struct net_device *dev)
 	flexcan_write(priv->reg_ctrl_default & ~FLEXCAN_CTRL_ERR_ALL,
 		      &regs->ctrl);
 
-	if (priv->reg_xceiver)
-		regulator_disable(priv->reg_xceiver);
+	flexcan_transceiver_disable(priv);
 	priv->can.state = CAN_STATE_STOPPED;
 
 	return;