ACPI / LPSS: enable hard LLP for DMA

Right now the DMA support of hard LLP (*) is fused. Enable it via specific
message sent to SoC at run time.

(*) Hard LLP stands for the multi-block transfer feature of DMA controller
supported by hardware.

Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>