drm/vc4: kms: Convert to for_each_new_crtc_state

The vc4 atomic commit loop has an handrolled loop that is basically
identical to for_each_new_crtc_state, let's convert it to that helper.

Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Tested-by: Chanwoo Choi <cw00.choi@samsung.com>
Tested-by: Hoegeun Kwon <hoegeun.kwon@samsung.com>
Tested-by: Stefan Wahren <stefan.wahren@i2se.com>
Reviewed-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
Link: https://patchwork.freedesktop.org/patch/msgid/a712d2b70aaee20379cfc52c2141aa2f6e2a9d5b.1599120059.git-series.maxime@cerno.tech

drivers/gpu/drm/vc4/vc4_kms.c

@@ -152,14 +152,16 @@ vc4_atomic_complete_commit(struct drm_atomic_state *state)
 	struct drm_device *dev = state->dev;
 	struct vc4_dev *vc4 = to_vc4_dev(dev);
 	struct vc4_hvs *hvs = vc4->hvs;
-	struct vc4_crtc *vc4_crtc;
+	struct drm_crtc_state *new_crtc_state;
+	struct drm_crtc *crtc;
 	int i;
 
-	for (i = 0; i < dev->mode_config.num_crtc; i++) {
-		if (!state->crtcs[i].ptr || !state->crtcs[i].commit)
+	for_each_new_crtc_in_state(state, crtc, new_crtc_state, i) {
+		struct vc4_crtc *vc4_crtc = to_vc4_crtc(crtc);
+
+		if (!new_crtc_state->commit)
 			continue;
 
-		vc4_crtc = to_vc4_crtc(state->crtcs[i].ptr);
 		vc4_hvs_mask_underrun(dev, vc4_crtc->channel);
 	}