arm64: dts: qcom: align RPM regulators node name with bindings

Node names should be generic and new DT schema expects RPM regulators
node to be just "regulators".

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20220926092104.111449-3-krzysztof.kozlowski@linaro.org