dmaengine: dw-axi-dmac: Set constraint to the Max segment size

dmaengine: dw-axi-dmac: Set constraint to the Max segment size

Add support for DMA Scatter-Gather (SG) constraint so that DMA clients can
handle the AxiDMA limitation.

Without supporting DMA constraint the default Max segment size reported by
dmaengine is 64KB, which is not supported by Intel KeemBay AxiDMA.

Signed-off-by: Sia Jee Heng <jee.heng.sia@intel.com>
Tested-by: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
Link: https://lore.kernel.org/r/20210125013255.25799-17-jee.heng.sia@intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>