staging: media: tegra-video: improve error messages

tegra_vi_channels_alloc() can primarily fail for two reasons:

 1. "ports" node not found
 2. port_num > vi->soc->vi_max_channels

Case 1 prints nothing, case 2 has a dev_err(). The caller [tegra_vi_init()]
has a generic dev_err() on any failure. This mean that in case 2 we print
two messages, and in case 1 we only print a generic message.

Remove the generic message and add a specific message when case 1 happens,
so that we always have one specific message without even increasing the
number of dev_dbg*() calls.
Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
Reviewed-by: Dmitry Osipenko <digetx@gmail.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>

drivers/staging/media/tegra-video/vi.c

@@ -1363,7 +1363,7 @@ static int tegra_vi_channels_alloc(struct tegra_vi *vi)
 
 	ports = of_get_child_by_name(node, "ports");
 	if (!ports)
-		return -ENODEV;
+		return dev_err_probe(vi->dev, -ENODEV, "%pOF: missing 'ports' node\n", node);
 
 	for_each_child_of_node(ports, port) {
 		if (!of_node_name_eq(port, "port"))
@@ -1923,11 +1923,8 @@ static int tegra_vi_init(struct host1x_client *client)
 		ret = tegra_vi_tpg_channels_alloc(vi);
 	else
 		ret = tegra_vi_channels_alloc(vi);
-	if (ret < 0) {
-		dev_err(vi->dev,
-			"failed to allocate vi channels: %d\n", ret);
+	if (ret < 0)
 		goto free_chans;
-	}
 
 	ret = tegra_vi_channels_init(vi);
 	if (ret < 0)