iio: accel: adxl355: Fix alignment for DMA safety

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

Fixes: 327a0eaf19 ("iio: accel: adxl355: Add triggered buffer support")
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Puranjay Mohan <puranjay12@gmail.com>
Acked-by: Nuno Sá <nuno.sa@analog.com>
Link: https://lore.kernel.org/r/20220508175712.647246-4-jic23@kernel.org

drivers/iio/accel/adxl355_core.c

@@ -177,7 +177,7 @@ struct adxl355_data {
 			u8 buf[14];
 			s64 ts;
 		} buffer;
-	} ____cacheline_aligned;
+	} __aligned(IIO_DMA_MINALIGN);
 };
 
 static int adxl355_set_op_mode(struct adxl355_data *data,