fbdev: au1200fb: Fix missing IRQ check in au1200fb_drv_probe

This func misses checking for platform_get_irq()'s call and may passes the
negative error codes to request_irq(), which takes unsigned IRQ #,
causing it to fail with -EINVAL, overriding an original error code.

Fix this by stop calling request_irq() with invalid IRQ #s.

Fixes: 1630d85 ("au1200fb: fix hardcoded IRQ")
Signed-off-by: Zhang Shurong <zhang_shurong@foxmail.com>
Signed-off-by: Helge Deller <deller@gmx.de>

Author: ZhangShurong

drivers/video/fbdev/au1200fb.c

@@ -1732,6 +1732,9 @@ static int au1200fb_drv_probe(struct platform_device *dev)
 
 	/* Now hook interrupt too */
 	irq = platform_get_irq(dev, 0);
+	if (irq < 0)
+		return irq;
+
 	ret = request_irq(irq, au1200fb_handle_irq,
 			  IRQF_SHARED, "lcd", (void *)dev);
 	if (ret) {