iio: accel: adxl367: fix I2C FIFO data register

iio: accel: adxl367: fix I2C FIFO data register

As specified in the datasheet, the I2C FIFO data register is
0x18, not 0x42. 0x42 was used by mistake when adapting the
ADXL372 driver.

Fix this mistake.

Fixes: cbab791c5e2a ("iio: accel: add ADXL367 driver")
Signed-off-by: Cosmin Tanislav <demonsingur@gmail.com>
Reviewed-by: Nuno Sa <nuno.sa@analog.com>
Link: https://lore.kernel.org/r/20240207033657.206171-2-demonsingur@gmail.com
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>