arm64: dts: qcom: sm8350: correct DMA controller unit address

Match unit-address to reg entry to fix dtbs W=1 warnings:

  Warning (simple_bus_reg): /soc@0/dma-controller@900000: simple-bus unit address format error, expected "9800000"

Fixes: bc08fbf4 ("arm64: dts: qcom: sm8350: Define GPI DMA engines")
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20230419211856.79332-13-krzysztof.kozlowski@linaro.org