drm/i915/mtl: Add display power wells

drm/i915/mtl: Add display power wells

Add support for display power wells on MTL. The differences from XE_LPD:
- The AUX HW block is moved to the PICA block, where the registers are on
  an always-on power well and the functionality needs to be powered on/off
  via the AUX_CH_CTL register: [1], [2]
- The DDI IO power on/off programming sequence is moved to the PHY PLL
  enable/disable sequence. [3], [4], [5]

Bspec: [1] 49233, [2] 65247, [3] 64568, [4] 65451, [5] 65450

v2:
 - Update the comment in aux power well enable
 - Reuse the noop sync fn for aux sync.
 - Use REG_BIT for new register bit definitions

Signed-off-by: Imre Deak <imre.deak@intel.com>
Signed-off-by: Radhakrishna Sripada <radhakrishna.sripada@intel.com>
Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220902060342.151824-7-radhakrishna.sripada@intel.com