iio: light: tcs3472: do not free unallocated IRQ

Allocating an IRQ is conditional to the IRQ existence, but freeing it
was not. If no IRQ was allocate, the driver would still try to free
IRQ 0. Add the missing checks.

This fixes the following trace when the driver is removed:

[  100.667788] Trying to free already-free IRQ 0
[  100.667793] WARNING: CPU: 0 PID: 2315 at kernel/irq/manage.c:1826 free_irq+0x1fd/0x370
...
[  100.667914] Call Trace:
[  100.667920]  tcs3472_remove+0x3a/0x90 [tcs3472]
[  100.667927]  i2c_device_remove+0x2b/0xa0
Signed-off-by: frank zago <frank@zago.net>
Link: https://lore.kernel.org/r/20210427022017.19314-2-frank@zago.net
Fixes: 9d2f715d ("iio: light: tcs3472: support out-of-threshold events")
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/light/tcs3472.c

@@ -535,7 +535,8 @@ static int tcs3472_probe(struct i2c_client *client,
 	return 0;
 
 free_irq:
-	free_irq(client->irq, indio_dev);
+	if (client->irq)
+		free_irq(client->irq, indio_dev);
 buffer_cleanup:
 	iio_triggered_buffer_cleanup(indio_dev);
 	return ret;
@@ -563,7 +564,8 @@ static int tcs3472_remove(struct i2c_client *client)
 	struct iio_dev *indio_dev = i2c_get_clientdata(client);
 
 	iio_device_unregister(indio_dev);
-	free_irq(client->irq, indio_dev);
+	if (client->irq)
+		free_irq(client->irq, indio_dev);
 	iio_triggered_buffer_cleanup(indio_dev);
 	tcs3472_powerdown(iio_priv(indio_dev));