iio: chemical: ams-iaq-core: clean up codestyle warning

This fixes a checkpatch warning by changing the struct attribute from __attribute__((__packed__)) to __packed.
Signed-off-by: Bruna Bispo <blbispo1@gmail.com>
Link: https://lore.kernel.org/r/20240528143816.13409-1-blbispo1@gmail.comSigned-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/chemical/ams-iaq-core.c

@@ -24,7 +24,7 @@ struct ams_iaqcore_reading {
 	u8 status;
 	__be32 resistance;
 	__be16 voc_ppb;
-} __attribute__((__packed__));
+} __packed;
 
 struct ams_iaqcore_data {
 	struct i2c_client *client;