Allow first power mode as off state

Bug: 237745199
test: atest libsurfaceflinger_unittest:OnInitializeDisplaysTest
      atest libsurfaceflinger_unittest:SetPowerModeInternalTest
Merged-In: I3a2eae4efc4a5c6113700a9ca9e9b261e364a878
Change-Id: I3a2eae4efc4a5c6113700a9ca9e9b261e364a878
4 files changed