can: tcan4x5x: tcan4x5x_can_probe(): add missing error handling if mcan_class is NULL

This patch adds the missing error handling in tcan4x5x_can_probe() if
mcan_class is NULL.

Fixes: 5443c226 ("can: tcan4x5x: Add tcan4x5x driver to the kernel")
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

drivers/net/can/m_can/tcan4x5x.c

@@ -414,6 +414,9 @@ static int tcan4x5x_can_probe(struct spi_device *spi)
 	int freq, ret;
 
 	mcan_class = m_can_class_allocate_dev(&spi->dev);
+	if (!mcan_class)
+		return -ENOMEM;
+
 	priv = devm_kzalloc(&spi->dev, sizeof(*priv), GFP_KERNEL);
 	if (!priv)
 		return -ENOMEM;