iio: adc: dln2: Use aligned_s64 for timestamp

iio: adc: dln2: Use aligned_s64 for timestamp

Here the lack of marking allows the overall structure to not be
sufficiently aligned resulting in misplacement of the timestamp
in iio_push_to_buffers_with_timestamp(). Use aligned_s64 to
force the alignment on all architectures.

Fixes: 7c0299e879dd ("iio: adc: Add support for DLN2 ADC")
Reported-by: David Lechner <dlechner@baylibre.com>
Reviewed-by: Andy Shevchenko <andy@kernel.org>
Reviewed-by: Nuno Sá <nuno.sa@analog.com>
Reviewed-by: David Lechner <dlechner@baylibre.com>
Link: https://patch.msgid.link/20250413103443.2420727-4-jic23@kernel.org
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>