arm64: dts: hi3660: Add dma to uart nodes

Try to add DMA support to the uart nodes following
the assignments made in the dts from the victoria vendor kernel
here:
https://consumer.huawei.com/en/opensource/detail/?siteCode=worldwide&keywords=p10&fileType=openSourceSoftware&pageSize=10&curPage=1



Cc: Tanglei Han <hantanglei@huawei.com>
Cc: Zhuangluan Su <suzhuangluan@hisilicon.com>
Cc: Ryan Grachek <ryan@edited.us>
Cc: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Cc: Wei Xu <xuwei5@hisilicon.com>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: devicetree@vger.kernel.org
Acked-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Wei Xu <xuwei5@hisilicon.com>