iio: pressure: mprls0025pa: fix scan_type struct

iio: pressure: mprls0025pa: fix scan_type struct

Fix the scan_type sign and realbits assignment.

The pressure is a 24bit unsigned int between output_min and output_max.

 transfer function A: 10%   to 90%   of 2^24
 transfer function B:  2.5% to 22.5% of 2^24
 transfer function C: 20%   to 80%   of 2^24
[MPR_FUNCTION_A] = { .output_min = 1677722, .output_max = 15099494 }
[MPR_FUNCTION_B] = { .output_min =  419430, .output_max =  3774874 }
[MPR_FUNCTION_C] = { .output_min = 3355443, .output_max = 13421773 }

Fixes: 713337d9143e ("iio: pressure: Honeywell mprls0025pa pressure sensor")
Signed-off-by: Petre Rodan <petre.rodan@subdimension.ro>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@intel.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>