arm64: Make default dma_ops to be noncoherent

arm64: Make default dma_ops to be noncoherent

Currently arm64 dma_ops is by default made coherent which makes it
opposite in default policy from arm.

Make default dma_ops to be noncoherent (same as arm), as currently there
aren't any dma-capable drivers which assumes coherent ops

Signed-off-by: Ritesh Harjani <ritesh.harjani@gmail.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
(cherry picked from commit c7a4a7658d689f664050c45493d79adf053f226e)

Signed-off-by: Jon Medhurst <tixy@linaro.org>
Signed-off-by: Mark Brown <broonie@linaro.org>