dmaengine: dw-edma: Add CPU to PCIe bus address translation

Starting from commit 95756320 ("dmaengine: make slave address
physical") the source and destination addresses of the DMA-slave device
have been converted to being defined in CPU address space. It's DMA-device
driver responsibility to properly convert them to the reachable DMA bus
spaces. In case of the DW eDMA device, the source or destination
peripheral (slave) devices reside PCIe bus space. Thus we need to perform
the PCIe Host/EP windows-based (i.e. ranges DT-property) addresses
translation otherwise the eDMA transactions won't work as expected (or can
be even harmful) in case if the CPU and PCIe address spaces don't match.

Note 1. Even though the DMA interleaved template has both source and
destination addresses declared of dma_addr_t type only CPU memory range is
supposed to be mapped in a way so to be seen by the DMA device since it's
a subject of the DMA getting towards the system side. The device part must
not be mapped since slave device resides in the PCIe bus space, which
isn't affected by IOMMUs or iATU translations. DW PCIe eDMA generates
corresponding MWr/MRd TLPs on its own.

Note 2. This functionality is mainly required for the remote eDMA setup
since the CPU address must be manually translated into the PCIe bus space
before being written to LLI.{SAR,DAR}. If eDMA is embedded into the
locally accessible DW PCIe RP/EP software-based translation isn't required
since it will be done by hardware by means of the Outbound iATU as long as
the DMA_BYPASS flag is cleared. If the later flag is set or there is no
Outbound iATU entry found to which the SAR or DAR falls in (for Read and
Write channel respectfully), there won't be any translation performed but
DMA will proceed with the corresponding source/destination address as is.

Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Tested-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Acked-By: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>