phy: fsl-imx8mq-usb: add dev_err_probe if getting vbus failed

This adds an error message if getting vbus failed for some reason,
-EPROBE_DEFER is handled appropriately as well and adds a nice
information to debugfs.

Signed-off-by: Alexander Stein <alexander.stein@ew.tq-group.com>
Link: https://lore.kernel.org/r/20230816080256.611380-1-alexander.stein@ew.tq-group.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

Author: tq-steina

drivers/phy/freescale/phy-fsl-imx8mq-usb.c

@@ -394,7 +394,7 @@ static int imx8mq_usb_phy_probe(struct platform_device *pdev)
 
 	imx_phy->vbus = devm_regulator_get(dev, "vbus");
 	if (IS_ERR(imx_phy->vbus))
-		return PTR_ERR(imx_phy->vbus);
+		return dev_err_probe(dev, PTR_ERR(imx_phy->vbus), "failed to get vbus\n");
 
 	phy_set_drvdata(imx_phy->phy, imx_phy);