drm: sti: hda: fix return value check in sti_hda_probe()

In case of error, the function devm_ioremap_nocache() returns NULL
pointer not ERR_PTR(). The IS_ERR() test in the return value check
should be replaced with NULL test.
Signed-off-by: NWei Yongjun <yongjun_wei@trendmicro.com.cn>

drivers/gpu/drm/sti/sti_hda.c

@@ -730,16 +730,16 @@ static int sti_hda_probe(struct platform_device *pdev)
 		return -ENOMEM;
 	}
 	hda->regs = devm_ioremap_nocache(dev, res->start, resource_size(res));
-	if (IS_ERR(hda->regs))
-		return PTR_ERR(hda->regs);
+	if (!hda->regs)
+		return -ENOMEM;
 
 	res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
 			"video-dacs-ctrl");
 	if (res) {
 		hda->video_dacs_ctrl = devm_ioremap_nocache(dev, res->start,
 				resource_size(res));
-		if (IS_ERR(hda->video_dacs_ctrl))
-			return PTR_ERR(hda->video_dacs_ctrl);
+		if (!hda->video_dacs_ctrl)
+			return -ENOMEM;
 	} else {
 		/* If no existing video-dacs-ctrl resource continue the probe */
 		DRM_DEBUG_DRIVER("No video-dacs-ctrl resource\n");