iio: chemical: bme680: Sort headers alphabetically

Sort headers in alphabetical order and split the iio specific functions
with a blank line

Signed-off-by: Vasileios Amoiridis <vassilisamir@gmail.com>
Link: https://patch.msgid.link/20240609233826.330516-6-vassilisamir@gmail.com


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