dt-bindings: soc: qcom: qcom,rpm: add missing clock/-names properties

Qualcomm MSM8660 and IPQ0864 platforms use additional clock for the RPM
device. Document it in the schema.

Fixes: aa0c4b81 ("mfd: devicetree: bindings: Add Qualcomm RPM DT binding")
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Reviewed-by: Rob Herring (Arm) <robh@kernel.org>
Link: https://lore.kernel.org/r/20250318-fix-nexus-4-v2-2-bcedd1406790@oss.qualcomm.com


Signed-off-by: Bjorn Andersson <andersson@kernel.org>