iio:temperature:mlx90632: Add kerneldoc to the internal struct

#define MLX90632_MAX_MEAS_NUM	31 /**< Maximum measurements in list */

#define MLX90632_SLEEP_DELAY_MS 3000 /**< Autosleep delay */

/**

 * struct mlx90632_data - private data for the MLX90632 device

 * @client: I2C client of the device

 * @lock: Internal mutex for multiple reads for single measurement

 * @regmap: Regmap of the device

 * @emissivity: Object emissivity from 0 to 1000 where 1000 = 1.

 */

struct mlx90632_data {

	struct i2c_client *client;

	struct mutex lock; /* Multiple reads for single measurement */

	struct mutex lock;

	struct regmap *regmap;

	u16 emissivity;

};