iio: accel: sca3000: Fix alignment for DMA safety

____cacheline_aligned is insufficient guarantee for non-coherent DMA.
Switch to the updated IIO_DMA_MINALIGN definition.

The second alignment marking is left in place to avoid doing more than
the simple fix in this patch.

Fixes: ced5c03d ("staging:iio:accel:sca3000 merge files into one.")
Fixes: 152a6a88 ("staging:iio:accel:sca3000 move to hybrid hard / soft buffer design.")
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Acked-by: Nuno Sá <nuno.sa@analog.com>
Link: https://lore.kernel.org/r/20220508175712.647246-8-jic23@kernel.org