usb: musb: Silence error about blacklisting hubs if !CONFIG_USB

Some drivers, like jz4740-musb, don't depend on CONFIG_USB.
Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Signed-off-by: Bin Liu <b-liu@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/musb/musb_core.c

@@ -1497,10 +1497,11 @@ static int musb_core_init(u16 musb_type, struct musb *musb)
 	} else {
 		musb->is_multipoint = 0;
 		type = "";
-#ifndef	CONFIG_USB_OTG_BLACKLIST_HUB
-		pr_err("%s: kernel must blacklist external hubs\n",
-		       musb_driver_name);
-#endif
+		if (IS_ENABLED(CONFIG_USB) &&
+		    !IS_ENABLED(CONFIG_USB_OTG_BLACKLIST_HUB)) {
+			pr_err("%s: kernel must blacklist external hubs\n",
+			       musb_driver_name);
+		}
 	}
 
 	/* log release info */