iio: chemical: bme680: Allocate IIO device before chip initialization

Move the IIO device allocation before the actual initialization of the
chip to be more consistent with most IIO drivers and also to have the
ability to use any driver specific data for the chip initialization.

While at it, fix also a misaligned line.

Signed-off-by: Vasileios Amoiridis <vassilisamir@gmail.com>
Link: https://patch.msgid.link/20240609233826.330516-9-vassilisamir@gmail.com


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