iio: accel: replace s64 __aligned(8) with aligned_s64

iio: accel: replace s64 __aligned(8) with aligned_s64

e4ca0e59c394 ("types: Complement the aligned types with signed 64-bit one")
introduced aligned_s64. Use it for all IIO accelerometer drivers.

Reviewed-by: Nuno Sa <nuno.sa@analog.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Matti Vaittinen <mazziesaccount@gmail.com>
Link: https://patch.msgid.link/20241020180720.496327-1-jic23@kernel.org
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>