drm/tegra: hdmi: Silence deferred-probe error

Driver fails to probe with -EPROBE_DEFER, which produces a bit noisy error
message in KMSG during kernel's boot up. This happens because voltage
regulators tend to be probed later than the DRM driver.
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>

drivers/gpu/drm/tegra/hdmi.c

@@ -1648,6 +1648,7 @@ static irqreturn_t tegra_hdmi_irq(int irq, void *data)
 
 static int tegra_hdmi_probe(struct platform_device *pdev)
 {
+	const char *level = KERN_ERR;
 	struct tegra_hdmi *hdmi;
 	struct resource *regs;
 	int err;
@@ -1686,21 +1687,36 @@ static int tegra_hdmi_probe(struct platform_device *pdev)
 	}
 
 	hdmi->hdmi = devm_regulator_get(&pdev->dev, "hdmi");
-	if (IS_ERR(hdmi->hdmi)) {
-		dev_err(&pdev->dev, "failed to get HDMI regulator\n");
-		return PTR_ERR(hdmi->hdmi);
+	err = PTR_ERR_OR_ZERO(hdmi->hdmi);
+	if (err) {
+		if (err == -EPROBE_DEFER)
+			level = KERN_DEBUG;
+
+		dev_printk(level, &pdev->dev,
+			   "failed to get HDMI regulator: %d\n", err);
+		return err;
 	}
 
 	hdmi->pll = devm_regulator_get(&pdev->dev, "pll");
-	if (IS_ERR(hdmi->pll)) {
-		dev_err(&pdev->dev, "failed to get PLL regulator\n");
-		return PTR_ERR(hdmi->pll);
+	err = PTR_ERR_OR_ZERO(hdmi->pll);
+	if (err) {
+		if (err == -EPROBE_DEFER)
+			level = KERN_DEBUG;
+
+		dev_printk(level, &pdev->dev,
+			   "failed to get PLL regulator: %d\n", err);
+		return err;
 	}
 
 	hdmi->vdd = devm_regulator_get(&pdev->dev, "vdd");
-	if (IS_ERR(hdmi->vdd)) {
-		dev_err(&pdev->dev, "failed to get VDD regulator\n");
-		return PTR_ERR(hdmi->vdd);
+	err = PTR_ERR_OR_ZERO(hdmi->vdd);
+	if (err) {
+		if (err == -EPROBE_DEFER)
+			level = KERN_DEBUG;
+
+		dev_printk(level, &pdev->dev,
+			   "failed to get VDD regulator: %d\n", err);
+		return err;
 	}
 
 	hdmi->output.dev = &pdev->dev;