iio: chemical: sps30: use aligned_s64 for timestamp

Follow the pattern of other drivers and use aligned_s64 for the
timestamp. This will ensure that the timestamp is correctly aligned on
all architectures.

Fixes: a5bf6fd ("iio:chemical:sps30: Fix timestamp alignment")
Signed-off-by: David Lechner <dlechner@baylibre.com>
Reviewed-by: Nuno Sá <nuno.sa@analog.com>
Link: https://patch.msgid.link/20250417-iio-more-timestamp-alignment-v1-5-eafac1e22318@baylibre.com
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/chemical/sps30.c

@@ -108,7 +108,7 @@ static irqreturn_t sps30_trigger_handler(int irq, void *p)
 	int ret;
 	struct {
 		s32 data[4]; /* PM1, PM2P5, PM4, PM10 */
-		s64 ts;
+		aligned_s64 ts;
 	} scan;
 
 	mutex_lock(&state->lock);