iio: accel: bma400: Reorganize and rename register and field macros

iio: accel: bma400: Reorganize and rename register and field macros

Reorganize register and field macros to improve consistency with the
datasheet and naming style:

- Move field macros next to their corresponding register macros
- Reorder register macros to follow address order from the datasheet
- Rename field macros to include the register name in the macro name
- Add a _REG suffix to register macros where missing
- Add INT_STAT register fields corresponding to used INT_CONFIG fields

No functional changes are intended.

Signed-off-by: Akshay Jindal <akshayaj.lkd@gmail.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>