arm64: dts: qcom: sm6115: Add watchdog node to dtsi

Add watchdog node in Qualcomm sm6115 SoC dtsi.

Signed-off-by: Bhupesh Sharma <bhupesh.sharma@linaro.org>
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20230119123200.1021735-1-bhupesh.sharma@linaro.org