iio: pressure: Fixes BMP38x and BMP390 SPI support

iio: pressure: Fixes BMP38x and BMP390 SPI support

According to the datasheet of BMP38x and BMP390 devices, for an SPI
read operation the first byte that is returned needs to be dropped,
and the rest of the bytes are the actual data returned from the
sensor.

Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Fixes: 8d329309184d ("iio: pressure: bmp280: Add support for BMP380 sensor family")
Signed-off-by: Vasileios Amoiridis <vassilisamir@gmail.com>
Acked-by: Angel Iglesias <ang.iglesiasg@gmail.com>
Link: https://lore.kernel.org/r/20240219191359.18367-1-vassilisamir@gmail.com
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>