iio: adc: ti-adc161s626: Fix alignment for DMA safety

____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: 4d671b71 ("iio: adc: ti-adc161s626: add support for TI 1-channel differential ADCs")
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Matt Ranostay <mranostay@gmail.com>
Acked-by: Nuno Sá <nuno.sa@analog.com>
Link: https://lore.kernel.org/r/20220508175712.647246-34-jic23@kernel.org

drivers/iio/adc/ti-adc161s626.c

@@ -71,7 +71,7 @@ struct ti_adc_data {
 	u8 read_size;
 	u8 shift;
 
-	u8 buffer[16] ____cacheline_aligned;
+	u8 buffer[16] __aligned(IIO_DMA_MINALIGN);
 };
 
 static int ti_adc_read_measurement(struct ti_adc_data *data,