iio: pressure: bmp280: Use BME prefix for BME280 specifics

Change the rest of the defines and function names that are
used specifically by the BME280 humidity sensor to BME280
as it is done for the rest of the BMP{0,1,3,5}80 sensors.

Signed-off-by: Vasileios Amoiridis <vassilisamir@gmail.com>
Link: https://lore.kernel.org/r/20240429190046.24252-3-vassilisamir@gmail.com


Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>