clk: qcom: Add TCSR clock driver for SM8550

The TCSR clock controller found on SM8550 provides refclks
for PCIE, USB and UFS. Add clock driver for it.

This patch is based on initial code downstream.

Signed-off-by: Abel Vesa <abel.vesa@linaro.org>
Reviewed-by: Konrad Dybcio <konrad.dybcio@linaro.org>