arm64: dts: qcom: sm8450: remove invalid power-domain-names in pcie nodes

Fixes the following DT bindings check error:
pci@1c00000: Unevaluated properties are not allowed ('power-domain-names' were unexpected)

Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20230323-topic-sm8450-upstream-dt-bindings-fixes-v2-3-0ca1bea1a843@linaro.org