USB: consolidate remote wakeup routines

This patch (as1324) makes a small change to the code used for remote
wakeup of root hubs.  hcd_resume_work() now calls the hub driver's
remote-wakeup routine instead of implementing its own version.

The patch is complicated by the need to rename remote_wakeup() to
usb_remote_wakeup(), make it non-static, and declare it in a header
file.  There's also the additional complication required to make
everything work when CONFIG_PM isn't set; the do-nothing inline
routine had to be moved into the header file.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/usb/core/usb.h b/drivers/usb/core/usb.h
index 4c36c7f..2b74a7f 100644
--- a/drivers/usb/core/usb.h
+++ b/drivers/usb/core/usb.h
@@ -63,6 +63,7 @@
 		pm_message_t msg);
 extern int usb_external_resume_device(struct usb_device *udev,
 		pm_message_t msg);
+extern int usb_remote_wakeup(struct usb_device *dev);
 
 static inline void usb_pm_lock(struct usb_device *udev)
 {
@@ -86,6 +87,11 @@
 	return 0;
 }
 
+static inline int usb_remote_wakeup(struct usb_device *udev)
+{
+	return 0;
+}
+
 static inline void usb_pm_lock(struct usb_device *udev) {}
 static inline void usb_pm_unlock(struct usb_device *udev) {}