[media] vcodec: mediatek: Fix return value check in mtk_vcodec_init_enc_pm()

In case of error, the function devm_clk_get() returns ERR_PTR()
and not returns NULL. The NULL test in the return value check
should be replaced with IS_ERR().

Signed-off-by: Wei Yongjun <[e-mail]>
Signed-off-by: Hans Verkuil <[e-mail]>
Signed-off-by: Mauro Carvalho Chehab <[e-mail]>

drivers/media/platform/mtk-vcodec/mtk_vcodec_enc_pm.c

···
 	pm->dev = &pdev->dev;
 
 	pm->vencpll_d2 = devm_clk_get(&pdev->dev, "venc_sel_src");
-	if (pm->vencpll_d2 == NULL) {
+	if (IS_ERR(pm->vencpll_d2)) {
 		mtk_v4l2_err("devm_clk_get vencpll_d2 fail");
-		ret = -1;
+		ret = PTR_ERR(pm->vencpll_d2);
 	}
 
 	pm->venc_sel = devm_clk_get(&pdev->dev, "venc_sel");
-	if (pm->venc_sel == NULL) {
+	if (IS_ERR(pm->venc_sel)) {
 		mtk_v4l2_err("devm_clk_get venc_sel fail");
-		ret = -1;
+		ret = PTR_ERR(pm->venc_sel);
 	}
 
 	pm->univpll1_d2 = devm_clk_get(&pdev->dev, "venc_lt_sel_src");
-	if (pm->univpll1_d2 == NULL) {
+	if (IS_ERR(pm->univpll1_d2)) {
 		mtk_v4l2_err("devm_clk_get univpll1_d2 fail");
-		ret = -1;
+		ret = PTR_ERR(pm->univpll1_d2);
 	}
 
 	pm->venc_lt_sel = devm_clk_get(&pdev->dev, "venc_lt_sel");
-	if (pm->venc_lt_sel == NULL) {
+	if (IS_ERR(pm->venc_lt_sel)) {
 		mtk_v4l2_err("devm_clk_get venc_lt_sel fail");
-		ret = -1;
+		ret = PTR_ERR(pm->venc_lt_sel);
 	}
 
 	return ret;