arm64: dts: qcom: sm8250: Add support for SDC2

Add support for SDC2 which can be used to interface uSD card.

Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
[DB: minor fixes: clocks, iommus, opps]
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Link: https://lore.kernel.org/r/20201028190955.1264526-1-dmitry.baryshkov@linaro.org
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>