nios2: use generic dma_noncoherent_ops

Switch to the generic noncoherent direct mapping implementation.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Ley Foon Tan <ley.foon.tan@intel.com>
Tested-by: Ley Foon Tan <ley.foon.tan@intel.com>

arch/nios2/include/asm/Kbuild

@@ -9,6 +9,7 @@ generic-y += current.h
 generic-y += device.h
 generic-y += div64.h
 generic-y += dma.h
+generic-y += dma-mapping.h
 generic-y += emergency-restart.h
 generic-y += exec.h
 generic-y += extable.h