can: tcan4x5x: remove unused struct tcan4x5x_priv::tcan4x5x_lock

The mutex struct tcan4x5x_priv::tcan4x5x_lock is unused in the driver,
so this patch removes the variable from the driver.
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

drivers/net/can/m_can/tcan4x5x.c

@@ -113,7 +113,6 @@
 struct tcan4x5x_priv {
 	struct regmap *regmap;
 	struct spi_device *spi;
-	struct mutex tcan4x5x_lock; /* SPI device lock */
 
 	struct m_can_classdev *mcan_dev;
 
@@ -466,8 +465,6 @@ static int tcan4x5x_can_probe(struct spi_device *spi)
 	priv->regmap = devm_regmap_init(&spi->dev, &tcan4x5x_bus,
 					&spi->dev, &tcan4x5x_regmap);
 
-	mutex_init(&priv->tcan4x5x_lock);
-
 	tcan4x5x_power_enable(priv->power, 1);
 
 	ret = m_can_class_register(mcan_class);