drivers: can: mcan: merge nested if-statements into one

Merge two nested if-statements into one.

Signed-off-by: Henrik Brix Andersen <hebad@vestas.com>

drivers/can/can_mcan.c

@@ -1390,12 +1390,10 @@ int can_mcan_init(const struct device *dev)
 	k_mutex_init(&data->tx_mtx);
 	k_sem_init(&data->tx_sem, cbs->num_tx, cbs->num_tx);
 
-	if (config->common.phy != NULL) {
+	if (config->common.phy != NULL && !device_is_ready(config->common.phy)) {
-		if (!device_is_ready(config->common.phy)) {
 		LOG_ERR("CAN transceiver not ready");
 		return -ENODEV;
 	}
-	}
 
 	err = can_mcan_exit_sleep_mode(dev);
 	if (err != 0) {