dmaengine: call acpi_dma_request_slave_channel as well

The slave device could be enumerated by ACPI. In that case the
dma_request_slave_channel should use the acpi_dma_request_slave_channel()
helper.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>