iio: adc: ti-ads8688: Fix alignment for DMA safety

iio: adc: ti-ads8688: Fix alignment for DMA safety

[ Upstream commit a2105d87eb8eb03591515df10102e04a1c9e0e46 ]

____cacheline_aligned is an insufficient guarantee for non-coherent DMA
on platforms with 128 byte cachelines above L1.  Switch to the updated
IIO_DMA_MINALIGN definition.

Fixes: 3e87e7838328 ("iio: adc: Add TI ADS8688")
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Acked-by: Nuno Sá <nuno.sa@analog.com>
Link: https://lore.kernel.org/r/20220508175712.647246-39-jic23@kernel.org
Signed-off-by: Sasha Levin <sashal@kernel.org>