fix(mt8188): refine c-state power domain for extensibility

fix(mt8188): refine c-state power domain for extensibility

1. MT8188 uses "suspend to RAM" instead of "suspend to idle", so
   remove s2idle state.
2. Definition c-state power domain:
    - bit[7:4] (main state id):
      1: Cluster.
      2: Mcusys.
      3: Memory.
      4: System pll.
      5: System bus.
      6: SoC 26m/DCXO.
      7: Vcore buck.
      15: Suspend.
    - bit[3:0] (reserved for state_id extension):
      4: CPU buck.

Signed-off-by: Edward-JW Yang <edward-jw.yang@mediatek.corp-partner.google.com>
Change-Id: Ibacd3d642f78726e1f1c08f18892481d2695f9e6