iio: as3935: allocate correct iio_device size

Signed-off-by: George McCollister <george.mccollister@gmail.com>
Acked-by: Hartmut Knaack <knaack.h@gmx.de>
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

drivers/iio/proximity/as3935.c

@@ -330,7 +330,7 @@ static int as3935_probe(struct spi_device *spi)
 		return -EINVAL;
 	}
 
-	indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(st));
+	indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
 	if (!indio_dev)
 		return -ENOMEM;