iio: pressure: bmp280: Allow device to be enumerated from ACPI

There is no need to limit the driver use by OF/platform code.
In this case we simple remove redundant OF parts from the code.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>