drm/atomic: pass old crtc state to atomic_begin/flush.

In intel it's useful to keep track of some state changes with old
crtc state vs new state, for example to disable initial planes or
when a modeset's prevented during fastboot.

Cc: dri-devel@lists.freedesktop.org
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reviewed-by: Ander Conselvan de Oliveira <conselvan2@gmail.com>
[danvet: squash in fixup for exynos provided by Maarten.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_crtc.c

@@ -239,7 +239,8 @@ static int atmel_hlcdc_crtc_atomic_check(struct drm_crtc *c,
 	return atmel_hlcdc_plane_prepare_disc_area(s);
 }
 
-static void atmel_hlcdc_crtc_atomic_begin(struct drm_crtc *c)
+static void atmel_hlcdc_crtc_atomic_begin(struct drm_crtc *c,
+					  struct drm_crtc_state *old_s)
 {
 	struct atmel_hlcdc_crtc *crtc = drm_crtc_to_atmel_hlcdc_crtc(c);
 
@@ -253,7 +254,8 @@ static void atmel_hlcdc_crtc_atomic_begin(struct drm_crtc *c)
 	}
 }
 
-static void atmel_hlcdc_crtc_atomic_flush(struct drm_crtc *crtc)
+static void atmel_hlcdc_crtc_atomic_flush(struct drm_crtc *crtc,
+					  struct drm_crtc_state *old_s)
 {
 	/* TODO: write common plane control register if available */
 }