arm64: dts: qcom: sa8450p-pmics: add rtc node

Add the rtc block on the first pmic to enable the rtc for sa8540p-ride.

Signed-off-by: Eric Chanudet <echanude@redhat.com>
Reviewed-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Tested-by: Andrew Halaney <ahalaney@redhat.com> # sa8540p-ride
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20221219191000.2570545-3-echanude@redhat.com