USB: usb-hub-driver-improve-use-of-ifdef fix

Fix CONFIG_PM=n build.

Cc: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

drivers/usb/core/hub.c

@@ -1895,6 +1895,8 @@ static inline int remote_wakeup(struct usb_device *udev)
 	return 0;
 }
 
+#define hub_suspend NULL
+#define hub_resume NULL
 #endif
 
 void usb_suspend_root_hub(struct usb_device *hdev)