arm64: dts: qcom: sm6115: Provide real SMD RPM XO to SDC1/2

Since we have a functioning RPM clock driver, let's make use of it
and provide the real XO clock to clients, instead of the fixed-clock
stub.

Signed-off-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20221208201401.530555-3-konrad.dybcio@linaro.org