soc: qcom: rpmpd: Improve the naming

Now that we aren't bound by the preprocessor macros, improve the naming
to be a bit less preprocessor-y and touch up some rpmpd.pd.name fields
while at it.

Signed-off-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20230313-topic-rpmpd-v3-6-06a4f448ff90@linaro.org