drm/msm/dsi: fix irq_of_parse_and_map() error checking

The irq_of_parse_and_map() function returns zero on error. It
never returns negative error codes. Fix the check.

Fixes: a689554ba6ed ("drm/msm: Initial add DSI connector support")
Signed-off-by: Dan Carpenter <[e-mail]>
Reviewed-by: Konrad Dybcio <[e-mail]>
Reviewed-by: Abhinav Kumar <[e-mail]>
Patchwork: https://patchwork.freedesktop.org/patch/557715/
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Abhinav Kumar <[e-mail]>

drivers/gpu/drm/msm/dsi/dsi_host.c

···
 	}
 
 	msm_host->irq = irq_of_parse_and_map(pdev->dev.of_node, 0);
-	if (msm_host->irq < 0) {
-		ret = msm_host->irq;
-		dev_err(&pdev->dev, "failed to get irq: %d\n", ret);
-		return ret;
+	if (!msm_host->irq) {
+		dev_err(&pdev->dev, "failed to get irq\n");
+		return -EINVAL;
 	}
 
 	/* do not autoenable, will be enabled later */