arm64: dts: qcom: sm8250: Drop tcsr_mutex syscon

arm64: dts: qcom: sm8250: Drop tcsr_mutex syscon

Now that we don't need the intermediate syscon to represent the TCSR
mutexes, update the dts to describe the TCSR mutex directly under /soc.

Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Link: https://lore.kernel.org/r/20200622075956.171058-5-bjorn.andersson@linaro.org
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>