drm/nouveau: Use private save/restore hooks for CRTCs

I want to remove the core ones since with atomic drivers system
suspend/resume is solved much differently. And there's only 2 drivers
(gma500 besides nouveau) really using them.

v2: Fixup bugs Ilia spotted.

Cc: Ben Skeggs <bskeggs@redhat.com>
Cc: Ilia Mirkin <imirkin@alum.mit.edu>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1449245618-1127-1-git-send-email-daniel.vetter@ffwll.ch
Reviewed-by: Thierry Reding <treding@nvidia.com>

drivers/gpu/drm/nouveau/dispnv04/crtc.c

@@ -1081,8 +1081,6 @@ nouveau_crtc_set_config(struct drm_mode_set *set)
 }
 
 static const struct drm_crtc_funcs nv04_crtc_funcs = {
-	.save = nv_crtc_save,
-	.restore = nv_crtc_restore,
 	.cursor_set = nv04_crtc_cursor_set,
 	.cursor_move = nv04_crtc_cursor_move,
 	.gamma_set = nv_crtc_gamma_set,
@@ -1123,6 +1121,9 @@ nv04_crtc_create(struct drm_device *dev, int crtc_num)
 	nv_crtc->index = crtc_num;
 	nv_crtc->last_dpms = NV_DPMS_CLEARED;
 
+	nv_crtc->save = nv_crtc_save;
+	nv_crtc->restore = nv_crtc_restore;
+
 	drm_crtc_init(dev, &nv_crtc->base, &nv04_crtc_funcs);
 	drm_crtc_helper_add(&nv_crtc->base, &nv04_crtc_helper_funcs);
 	drm_mode_crtc_set_gamma_size(&nv_crtc->base, 256);