r8169: add missing conditional compiling for call to r8169_remove_leds

Add missing dependency on CONFIG_R8169_LEDS. As-is a link error occurs
if config option CONFIG_R8169_LEDS isn't enabled.

Fixes: 19fa4f2 ("r8169: fix LED-related deadlock on module removal")
Reported-by: Venkat Rao Bagalkote <venkat88@linux.vnet.ibm.com>
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Tested-By: Venkat Rao Bagalkote <venkat88@linux.vnet.ibm.com>
Link: https://lore.kernel.org/r/d080038c-eb6b-45ac-9237-b8c1cdd7870f@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Author: hkallweit

drivers/net/ethernet/realtek/r8169_main.c

@@ -5046,7 +5046,8 @@ static void rtl_remove_one(struct pci_dev *pdev)
 
 	cancel_work_sync(&tp->wk.work);
 
-	r8169_remove_leds(tp->leds);
+	if (IS_ENABLED(CONFIG_R8169_LEDS))
+		r8169_remove_leds(tp->leds);
 
 	unregister_netdev(tp->dev);