drm: Conslidate blending properties in drm_blend.[hc]

Imo zpos, rotatation, blending eq (once we have it) and all that
should be in drm_blend.c, since those are all about how exactly the
pixels are rendered onto the CRTC's visible area. Also noticed that
one exported function accidentally ended up in drm_crtc_internal.h,
move it to the right place too.

Reviewed-by: Sean Paul <seanpaul@chromium.org>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Signed-off-by: Sean Paul <seanpaul@chromium.org>
Link: http://patchwork.freedesktop.org/patch/msgid/1474448370-32227-3-git-send-email-daniel.vetter@ffwll.ch

drivers/gpu/drm/drm_crtc_internal.h

@@ -165,9 +165,6 @@ int drm_mode_atomic_ioctl(struct drm_device *dev,
 int drm_modeset_register_all(struct drm_device *dev);
 void drm_modeset_unregister_all(struct drm_device *dev);
 
-/* drm_blend.c */
-int drm_atomic_normalize_zpos(struct drm_device *dev,
-			      struct drm_atomic_state *state);
 
 /* drm_plane.c */
 int drm_plane_register_all(struct drm_device *dev);