iio: magn: rm3100: Fix alignment of buffer in iio_push_to_buffers_with_timestamp()

Add __aligned(8) to ensure the buffer passed to
iio_push_to_buffers_with_timestamp() is suitable for the naturally
aligned timestamp that will be inserted.

Here an explicit structure is not used, because this buffer is used in
a non-trivial way for data repacking.

Fixes: 121354b2eceb ("iio: magnetometer: Add driver support for PNI RM3100")
Signed-off-by: Jonathan Cameron <[e-mail]>
Cc: Song Qiang <[e-mail]>
Reviewed-by: Nuno Sá <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]

drivers/iio/magnetometer/rm3100-core.c

···
 	bool use_interrupt;
 	int conversion_time;
 	int scale;
-	u8 buffer[RM3100_SCAN_BYTES];
+	/* Ensure naturally aligned timestamp */
+	u8 buffer[RM3100_SCAN_BYTES] __aligned(8);
 	struct iio_trigger *drdy_trig;
 
 	/*