dm: treewide: Use uclass_first_device_err when accessing one device

There is a number of users that use uclass_first_device to access the
first and (assumed) only device in uclass.

Some check the return value of uclass_first_device and also that a
device was returned which is exactly what uclass_first_device_err does.

Some are not checking that a device was returned and can potentially
crash if no device exists in the uclass. Finally there is one that
returns NULL on error either way.

Convert all of these to use uclass_first_device_err instead, the return
value will be removed from uclass_first_device in a later patch.

Signed-off-by: Michal Suchanek <msuchanek@suse.de>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/video/exynos/exynos_fb.c b/drivers/video/exynos/exynos_fb.c
index 69992b3..86970a6 100644
--- a/drivers/video/exynos/exynos_fb.c
+++ b/drivers/video/exynos/exynos_fb.c
@@ -640,25 +640,17 @@
 #endif
 	exynos_fimd_lcd_init(dev);
 
-	ret = uclass_first_device(UCLASS_PANEL, &panel);
+	ret = uclass_first_device_err(UCLASS_PANEL, &panel);
 	if (ret) {
-		printf("LCD panel failed to probe\n");
+		printf("%s: LCD panel failed to probe %d\n", __func__, ret);
 		return ret;
 	}
-	if (!panel) {
-		printf("LCD panel not found\n");
-		return -ENODEV;
-	}
 
-	ret = uclass_first_device(UCLASS_DISPLAY, &dp);
+	ret = uclass_first_device_err(UCLASS_DISPLAY, &dp);
 	if (ret) {
 		debug("%s: Display device error %d\n", __func__, ret);
 		return ret;
 	}
-	if (!dev) {
-		debug("%s: Display device missing\n", __func__);
-		return -ENODEV;
-	}
 	ret = display_enable(dp, 18, NULL);
 	if (ret) {
 		debug("%s: Display enable error %d\n", __func__, ret);
diff --git a/drivers/video/mali_dp.c b/drivers/video/mali_dp.c
index ba1ddd6..cbcdb99 100644
--- a/drivers/video/mali_dp.c
+++ b/drivers/video/mali_dp.c
@@ -244,7 +244,7 @@
 	struct udevice *disp_dev;
 	int err;
 
-	err = uclass_first_device(UCLASS_DISPLAY, &disp_dev);
+	err = uclass_first_device_err(UCLASS_DISPLAY, &disp_dev);
 	if (err)
 		return err;
 
diff --git a/drivers/video/stm32/stm32_dsi.c b/drivers/video/stm32/stm32_dsi.c
index 5871ac7..e6347bb 100644
--- a/drivers/video/stm32/stm32_dsi.c
+++ b/drivers/video/stm32/stm32_dsi.c
@@ -346,7 +346,7 @@
 	struct display_timing timings;
 	int ret;
 
-	ret = uclass_first_device(UCLASS_PANEL, &priv->panel);
+	ret = uclass_first_device_err(UCLASS_PANEL, &priv->panel);
 	if (ret) {
 		dev_err(dev, "panel device error %d\n", ret);
 		return ret;
diff --git a/drivers/video/tegra124/dp.c b/drivers/video/tegra124/dp.c
index ee4f09a..b27b163 100644
--- a/drivers/video/tegra124/dp.c
+++ b/drivers/video/tegra124/dp.c
@@ -1494,8 +1494,8 @@
 		return -ENOLINK;
 	}
 
-	ret = uclass_first_device(UCLASS_VIDEO_BRIDGE, &sor);
-	if (ret || !sor) {
+	ret = uclass_first_device_err(UCLASS_VIDEO_BRIDGE, &sor);
+	if (ret) {
 		debug("dp: failed to find SOR device: ret=%d\n", ret);
 		return ret;
 	}