drm/i915: Kill intel_crtc->cursor_{width, height} (v2)

The cursor size fields in intel_crtc just duplicate the data from
cursor->state.crtc_{w,h} so we don't need them any more.  Worse, their
use in the watermark code actually introduces a subtle bug since they
don't get updated to mirror the state values until the plane commit
stage, which is *after* we've already used them to calculate new
watermark values.  This happens because we had to move watermark updates
slightly earlier (outside vblank evasion) in commit

        commit 32b7eeec


        Author: Matt Roper <matthew.d.roper@intel.com>
        Date:   Wed Dec 24 07:59:06 2014 -0800

            drm/i915: Refactor work that can sleep out of commit (v7)

Dropping the intel_crtc fields and just using the state values (which
are properly updated by the time watermark updates happen) should solve
the problem.

Aside from the actual removal of the struct fields (which are formatted
in a way that I couldn't figure out how to match in Coccinelle), the
rest of this patch was generated via the following semantic patch:

        // Drop assignment
        @@
        struct intel_crtc *C;
        struct drm_plane_state S;
        @@
        (
        - C->cursor_width = S.crtc_w;
        |
        - C->cursor_height = S.crtc_h;
        )

        // Replace usage
        @@
        struct intel_crtc *C;
        expression E;
        @@
        (
        - C->cursor_width
        + C->base.cursor->state->crtc_w
        |
        - C->cursor_height
        + C->base.cursor->state->crtc_h
        |
        - to_intel_crtc(E)->cursor_width
        + E->cursor->state->crtc_w
        |
        - to_intel_crtc(E)->cursor_height
        + E->cursor->state->crtc_h
        )

v2: Rebase

Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Joe Konno <joe.konno@linux.intel.com>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=89346
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>