drm/msm/dp: 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 an negative value.

Fixes: 8ede2ecc ("drm/msm/dp: Add DP compliance tests on Snapdragon Chipsets")
Reported-by: Zeal Robot <zealci@zte.com.cn>
Signed-off-by: Lv Ruyi <lv.ruyi@zte.com.cn>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Patchwork: https://patchwork.freedesktop.org/patch/483176/
Link: https://lore.kernel.org/r/20220424032418.3173632-1-lv.ruyi@zte.com.cnSigned-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>

drivers/gpu/drm/msm/dp/dp_display.c

@@ -1278,10 +1278,9 @@ int dp_display_request_irq(struct msm_dp *dp_display)
 	dp = container_of(dp_display, struct dp_display_private, dp_display);
 
 	dp->irq = irq_of_parse_and_map(dp->pdev->dev.of_node, 0);
-	if (dp->irq < 0) {
-		rc = dp->irq;
-		DRM_ERROR("failed to get irq: %d\n", rc);
-		return rc;
+	if (!dp->irq) {
+		DRM_ERROR("failed to get irq\n");
+		return -EINVAL;
 	}
 
 	rc = devm_request_irq(&dp->pdev->dev, dp->irq,