arm64: dts: qcom: msm8996: User generic node name for DMA

Qcom BAM DT spec expects generic DMA controller node name as
"dma-controller" to enable validations.

Signed-off-by: Kuldeep Singh <singh.kuldeep87k@gmail.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/20220410175056.79330-4-singh.kuldeep87k@gmail.com