This board uses RPMH, specifies "regulator-allow-set-load" for LDOs,
but doesn't specify any modes with "regulator-allowed-modes".

Prior to commit efb0cb50 ("regulator: qcom-rpmh: Implement
get_optimum_mode(), not set_load()") the above meant that we were able
to set either LPM or HPM mode. After that commit (and fixes [1]) we'll
be stuck at the initial mode. Discussion of this has resulted in the
decision that the old dts files were wrong and should be fixed to
fully restore old functionality.

Let's re-enable the old functionality by fixing the dts.

NOTE: while here, let's also remove the nonsensical
"regulator-allow-set-load" on the fixed regulator "vreg_s4a_1p8".

[1] https://lore.kernel.org/r/20220824142229.RFT.v2.2.I6f77860e5cd98bf5c67208fa9edda4a08847c304@changeid

Fixes: 5b85e8f2 ("arm64: dts: qcom: sa8155p-adp: Add base dts file")
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Andrew Halaney <ahalaney@redhat.com>
Reviewed-by: Konrad Dybcio <konrad.dybcio@somainline.org>
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20220829094903.v2.1.Id59c32b560c4662d8b3697de2bd494d08d654806@changeid