soc: qcom: rpmpd: Unify Low Power Island definitions

Up until now, we had 2 separate entries for VDD_LPI[CM]X and
VDD_LPI_[CM]X which both pointed to the same RPM resource. Fix 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-v3-3-06a4f448ff90@linaro.org