pmdomain: qcom: rpmhpd: Drop SA8540P gfx.lvl

On SA8295P and SA8540P gfx.lvl is not provdied by rpmh, but rather is
handled by an external regulator (max20411). Drop gfx.lvl from the list
of power-domains exposed on this platform.

Fixes: f68f1cb3 ("soc: qcom: rpmhpd: add sc8280xp & sa8540p rpmh power-domains")
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Acked-by: Ulf Hansson <ulf.hansson@linaro.org>
Reviewed-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Link: https://lore.kernel.org/r/20240125-sa8295p-gpu-v4-4-7011c2a63037@quicinc.com


Signed-off-by: Bjorn Andersson <quic_bjorande@quicinc.com>