media: pci: mg4b: use aligned_s64

media: pci: mg4b: use aligned_s64

Use aligned_s64 for IIO timestamp field instead of explicit __align().
This is the convention used throughout the IIO subsystem. No functional
change.

Suggested-by: Jonathan Cameron <jic23@kernel.org>
Closes: https://lore.kernel.org/linux-iio/20250724115610.011110fb@jic23-huawei/
Signed-off-by: David Lechner <dlechner@baylibre.com>
Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com>
Signed-off-by: Hans Verkuil <hverkuil+cisco@kernel.org>