drm/i915: Use passed plane state for sprite planes, v4.

drm/i915: Use passed plane state for sprite planes, v4.

Don't use plane->state directly, use the pointer from commit_plane.

Changes since v1:
- Fix uses of plane->state->rotation and color key to use the passed state too.
- Only pass crtc_state and plane_state to update_plane.
Changes since v2:
- Rebased.
Changes since v3:
- Small whitespace changes and only assign 1 variable per line.
- Constify plane_state and crtc_state. (vsyrjala)

Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1452164052-21752-2-git-send-email-maarten.lankhorst@linux.intel.com
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>