Revert "dt-bindings: power: rpmpd: Add SM4250 support"

SM4250 and SM6115 use a shared device tree and the RPMPDs are
identical. There's no need for a separate entry, so remove it.

This reverts commit 45ac44ed.

Signed-off-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20230113152232.2624545-2-konrad.dybcio@linaro.org