drm/i915/skl: Eliminate usage of pipe_wm_parameters from SKL-style WM (v3)

Just pull the info out of the state structures rather than staging
it in an additional set of structures.  To make this more
straightforward, we change the signature of several internal WM
functions to take the crtc state as a parameter.

v2:
 - Don't forget to skip cursor planes on a loop in the DDB allocation
   function to match original behavior.  (Ander)
 - Change a use of intel_crtc->active to cstate->active.  They should
   be identical, but it's better to be consistent.  (Ander)
 - Rework more function signatures to pass states rather than crtc for
   consistency. (Ander)

v3:
  - Add missing "+ 1" to skl_wm_plane_id()'s 'overlay' case. (Maarten)
  - Packed formats should pass '0' to drm_format_plane_cpp(), not 1.
    (Maarten)
  - Drop unwanted WARN_ON() for disabled planes when calculating data
    rate for SKL.  (Maarten)
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>