iio: adc: rockchip: correct alignment of timestamp

I assume this device is only used on architectures where a 8 byte
integer type is always 8 byte aligned.  However, I would prefer IIO
drivers to never make that assumption as the code gets copied into
new drivers which are not so tightly couple to one driver and those
can run on architectures that align these types to only 4 bytes in which
case this structure may be 4 byte to small leading to a buffer overrun.

Reviewed-by: Andy Shevchenko <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jonathan Cameron <[email protected]>

Author: jic23

drivers/iio/adc/rockchip_saradc.c

@@ -363,7 +363,7 @@ static irqreturn_t rockchip_saradc_trigger_handler(int irq, void *p)
 	 */
 	struct {
 		u16 values[SARADC_MAX_CHANNELS];
-		int64_t timestamp;
+		aligned_s64 timestamp;
 	} data;
 	int ret;
 	int i, j = 0;