iio: pressure: mprls0025pa: fix SPI CS delay violation

iio: pressure: mprls0025pa: fix SPI CS delay violation

Based on the sensor datasheet in chapter 7.6 SPI timing, Table 20,
during the SPI transfer there is a minimum time interval requirement
between the CS being asserted and the first clock edge (tHDSS).
This minimum interval of 2.5us is being violated if two consecutive SPI
transfers are queued up.

Fixes: a0858f0cd28e ("iio: pressure: mprls0025pa add SPI driver")
Datasheet: https://prod-edam.honeywell.com/content/dam/honeywell-edam/sps/siot/en-us/products/sensors/pressure-sensors/board-mount-pressure-sensors/micropressure-mpr-series/documents/sps-siot-mpr-series-datasheet-32332628-ciid-172626.pdf?download=false
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>