arm64: dts: qcom: sc7280: Remove unused sleep pin control nodes

Remove unused and redundant sleep pin control entries as they are
not referenced anywhere in sc7280 based platform's device tree variants.

Signed-off-by: Srinivasa Rao Mandadapu <quic_srivasam@quicinc.com>
Reported-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/1668591184-21099-1-git-send-email-quic_srivasam@quicinc.com