iio: imu: bno055: make bno055_sysfs_attr const

Add const qualifier to struct bno055_sysfs_attr and its array fields.
All of this is read-only data so it can be made const.

Signed-off-by: David Lechner <dlechner@baylibre.com>
Link: https://patch.msgid.link/20250709-iio-const-data-19-v2-2-fb3fc9191251@baylibre.com


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