drm/gma500: Fix wrong pointer passed to PTR_ERR()

PTR_ERR() should access the value just tested by IS_ERR(),
otherwise the wrong error code will be returned.
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>
Fixes: c2f17e60 ("drm/gma500: Embed struct drm_device in struct drm_psb_private")
Reported-by: Hulk Robot <hulkci@huawei.com>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Patrik Jakobsson <patrik.r.jakobsson@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210924094040.3631675-1-yangyingliang@huawei.com

drivers/gpu/drm/gma500/psb_drv.c

@@ -454,7 +454,7 @@ static int psb_pci_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 
 	dev_priv = devm_drm_dev_alloc(&pdev->dev, &driver, struct drm_psb_private, dev);
 	if (IS_ERR(dev_priv))
-		return PTR_ERR(dev);
+		return PTR_ERR(dev_priv);
 	dev = &dev_priv->dev;
 
 	pci_set_drvdata(pdev, dev);