drm: cleanup: drm_modeset_lock_all_ctx() --> DRM_MODESET_LOCK_ALL_BEGIN()

As requested in Documentation/gpu/todo.rst, replace the boilerplate code
surrounding drm_modeset_lock_all_ctx() with DRM_MODESET_LOCK_ALL_BEGIN()
and DRM_MODESET_LOCK_ALL_END()
Signed-off-by: Fernando Ramos <greenfoo@u92.eu>
Signed-off-by: Sean Paul <seanpaul@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20210924064324.229457-2-greenfoo@u92.eu

drivers/gpu/drm/drm_client_modeset.c

@@ -574,6 +574,7 @@ static bool drm_client_firmware_config(struct drm_client_dev *client,
 	int num_connectors_detected = 0;
 	int num_tiled_conns = 0;
 	struct drm_modeset_acquire_ctx ctx;
+	int err;
 
 	if (!drm_drv_uses_atomic_modeset(dev))
 		return false;
@@ -585,10 +586,7 @@ static bool drm_client_firmware_config(struct drm_client_dev *client,
 	if (!save_enabled)
 		return false;
 
-	drm_modeset_acquire_init(&ctx, 0);
-
-	while (drm_modeset_lock_all_ctx(dev, &ctx) != 0)
-		drm_modeset_backoff(&ctx);
+	DRM_MODESET_LOCK_ALL_BEGIN(dev, ctx, 0, err);
 
 	memcpy(save_enabled, enabled, count);
 	mask = GENMASK(count - 1, 0);
@@ -743,8 +741,7 @@ static bool drm_client_firmware_config(struct drm_client_dev *client,
 		ret = false;
 	}
 
-	drm_modeset_drop_locks(&ctx);
-	drm_modeset_acquire_fini(&ctx);
+	DRM_MODESET_LOCK_ALL_END(dev, ctx, err);
 
 	kfree(save_enabled);
 	return ret;