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: 327a0eaf19d53 ("iio: accel: adxl355: Add triggered buffer support")
Signed-off-by: Jonathan Cameron <[e-mail]>
Cc: Puranjay Mohan <[e-mail]>
Acked-by: Nuno Sá <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]

drivers/iio/accel/adxl355_core.c

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