drm/msm/dpu: fix error check return value of irq_of_parse_and_map()

The irq_of_parse_and_map() function returns 0 on failure, and does not
return a negative value anyhow, so never enter this conditional branch.

Fixes: 25fdd593 ("drm/msm: Add SDM845 DPU support")
Reported-by: Zeal Robot <zealci@zte.com.cn>
Signed-off-by: Lv Ruyi <lv.ruyi@zte.com.cn>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Patchwork: https://patchwork.freedesktop.org/patch/483291/
Link: https://lore.kernel.org/r/20220425090947.3498897-1-lv.ruyi@zte.com.cnSigned-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>

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

@@ -1183,9 +1183,9 @@ static int dpu_kms_init(struct drm_device *ddev)
 	priv->kms = &dpu_kms->base;
 
 	irq = irq_of_parse_and_map(dpu_kms->pdev->dev.of_node, 0);
-	if (irq < 0) {
-		DPU_ERROR("failed to get irq: %d\n", irq);
-		return irq;
+	if (!irq) {
+		DPU_ERROR("failed to get irq\n");
+		return -EINVAL;
 	}
 	dpu_kms->base.irq = irq;