parisc: led: fix reference leak on failed device registration

When platform_device_register() fails in startup_leds(), the embedded
struct device in platform_leds has already been initialized by
device_initialize(), but the failure path only reports the error and
does not drop the device reference for the current platform device:

  startup_leds()
    -> platform_device_register(&platform_leds)
       -> device_initialize(&platform_leds.dev)
       -> setup_pdev_dma_masks(&platform_leds)
       -> platform_device_add(&platform_leds)

This leads to a reference leak when platform_device_register() fails.
Fix this by calling platform_device_put() after reporting the error.

The issue was identified by a static analysis tool I developed and
confirmed by manual review.

Fixes: 789e527 ("parisc: led: Rewrite LED/LCD driver to utilizize Linux LED subsystem")
Cc: stable@vger.kernel.org
Signed-off-by: Guangshuo Li <lgs201920130244@gmail.com>
Signed-off-by: Helge Deller <deller@gmx.de>

Author: lgs2513

drivers/parisc/led.c

@@ -543,8 +543,10 @@ static void __init register_led_regions(void)
 
 static int __init startup_leds(void)
 {
-	if (platform_device_register(&platform_leds))
-                printk(KERN_INFO "LED: failed to register LEDs\n");
+	if (platform_device_register(&platform_leds)) {
+		pr_info("LED: failed to register LEDs\n");
+		platform_device_put(&platform_leds);
+	}
 	register_led_regions();
 	return 0;
 }