drm/i915: Add TGL+ SAGV support

drm/i915: Add TGL+ SAGV support

Starting from TGL we need to have a separate wm0
values for SAGV and non-SAGV which affects
how calculations are done.

v2: Remove long lines
v3: Removed COLOR_PLANE enum references
v4, v5, v6: Fixed rebase conflict
v7: - Removed skl_plane_wm_level accessor from skl_allocate_pipe_ddb(Ville)
    - Removed sagv_uv_wm0(Ville)
    - can_sagv->use_sagv_wm(Ville)

v8: - Moved tgl_crtc_can_enable_sagv function up(Ville)
    - Changed comment regarding pipe_wm usage(Ville)
    - Call intel_can_enable_sagv and tgl_compute_sagv_wm only
      for Gen12(Ville)
    - Some sagv debugs removed(Ville)
    - skl_print_wm_changes improvements(Ville)
    - Do assignment instead of memcpy in
      skl_pipe_wm_get_hw_state(Ville)

v9: - Removed can_sagv variable(Ville)
    - Removed spurious line(Ville)
    - Changed u32 to unsigned int as agreed(Ville)
    - Assign sagv only for gen12 in
      skl_pipe_wm_get_hw_state(Ville)

Signed-off-by: Stanislav Lisovskiy <stanislav.lisovskiy@intel.com>
[vsyrjala: Remove the dead 'return false' from intel_crtc_can_enable_sagv()]
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200514074853.9508-2-stanislav.lisovskiy@intel.com