iio: light: isl29125: Fix buffer alignment in iio_push_to_buffers_with_timestamp()

To make code more readable, use a structure to express the channel
layout and ensure the timestamp is 8 byte aligned.

Found during an audit of all calls of uses of
iio_push_to_buffers_with_timestamp()

Fixes: 6c25539c ("iio: Add Intersil isl29125 digital color light sensor driver")
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20210501170121.512209-18-jic23@kernel.org

drivers/iio/light/isl29125.c

@@ -51,7 +51,11 @@
 struct isl29125_data {
 	struct i2c_client *client;
 	u8 conf1;
-	u16 buffer[8]; /* 3x 16-bit, padding, 8 bytes timestamp */
+	/* Ensure timestamp is naturally aligned */
+	struct {
+		u16 chans[3];
+		s64 timestamp __aligned(8);
+	} scan;
 };
 
 #define ISL29125_CHANNEL(_color, _si) { \
@@ -184,10 +188,10 @@ static irqreturn_t isl29125_trigger_handler(int irq, void *p)
 		if (ret < 0)
 			goto done;
 
-		data->buffer[j++] = ret;
+		data->scan.chans[j++] = ret;
 	}
 
-	iio_push_to_buffers_with_timestamp(indio_dev, data->buffer,
+	iio_push_to_buffers_with_timestamp(indio_dev, &data->scan,
 		iio_get_time_ns(indio_dev));
 
 done: