drm/msm/dpu: fix error handling around dpu_hw_vbif_init

Using IS_ERR_OR_NULL() together with PTR_ERR() is a typical mistake. If
the value is NULL, then the function will return 0 instead of a proper
return code. Moreover dpu_hw_vbif_init() function can not return NULL.
So, replace corresponding IS_ERR_OR_NULL() call with IS_ERR().
Reviewed-by: Abhinav Kumar <quic_abhinavk@quicinc.com>
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Patchwork: https://patchwork.freedesktop.org/patch/489570/
Link: https://lore.kernel.org/r/20220615125703.24647-2-dmitry.baryshkov@linaro.orgSigned-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Signed-off-by: Rob Clark <robdclark@chromium.org>

drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c

@@ -1110,10 +1110,8 @@ static int dpu_kms_hw_init(struct msm_kms *kms)
 
 		dpu_kms->hw_vbif[vbif_idx] = dpu_hw_vbif_init(vbif_idx,
 				dpu_kms->vbif[vbif_idx], dpu_kms->catalog);
-		if (IS_ERR_OR_NULL(dpu_kms->hw_vbif[vbif_idx])) {
+		if (IS_ERR(dpu_kms->hw_vbif[vbif_idx])) {
 			rc = PTR_ERR(dpu_kms->hw_vbif[vbif_idx]);
-			if (!dpu_kms->hw_vbif[vbif_idx])
-				rc = -EINVAL;
 			DPU_ERROR("failed to init vbif %d: %d\n", vbif_idx, rc);
 			dpu_kms->hw_vbif[vbif_idx] = NULL;
 			goto power_error;