iio: adis16201: Correct inclinometer channel resolution

iio: adis16201: Correct inclinometer channel resolution

The inclinometer channels were previously defined with 14 realbits.
However, the ADIS16201 datasheet states the resolution for these output
channels is 12 bits (Page 14, text description; Page 15, table 7).

Correct the realbits value to 12 to accurately reflect the hardware.

Fixes: f7fe1d1dd5a5 ("staging: iio: new adis16201 driver")
Cc: stable@vger.kernel.org
Signed-off-by: Gabriel Shahrouzi <gshahrouzi@gmail.com>
Reviewed-by: Marcelo Schmitt <marcelo.schmitt1@gmail.com>
Link: https://patch.msgid.link/20250421131539.912966-1-gshahrouzi@gmail.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>