Since sata_dwc_460ex.c was moved to generic DMA driver we have to ensure that
user can still compile it.

Fixes: 8b344485 (sata_dwc_460ex: move to generic DMA driver)
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Tejun Heo <tj@kernel.org>