usb: hub: rename khubd to hub_wq in documentation and comments

USB hub has started to use a workqueue instead of kthread. Let's update
the documentation and comments here and there.

This patch mostly just replaces "khubd" with "hub_wq". There are only few
exceptions where the whole sentence was updated. These more complicated
changes can be found in the following files:

	   Documentation/usb/hotplug.txt
	   drivers/net/usb/usbnet.c
	   drivers/usb/core/hcd.c
	   drivers/usb/host/ohci-hcd.c
	   drivers/usb/host/xhci.c

Signed-off-by: Petr Mladek <pmladek@suse.cz>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/usb/core/hcd.c b/drivers/usb/core/hcd.c
index 761ccf0..d3fe161 100644
--- a/drivers/usb/core/hcd.c
+++ b/drivers/usb/core/hcd.c
@@ -2301,7 +2301,7 @@
  * Context: in_interrupt()
  *
  * Starts enumeration, with an immediate reset followed later by
- * khubd identifying and possibly configuring the device.
+ * hub_wq identifying and possibly configuring the device.
  * This is needed by OTG controller drivers, where it helps meet
  * HNP protocol timing requirements for starting a port reset.
  *
@@ -2320,7 +2320,7 @@
 	if (port_num && hcd->driver->start_port_reset)
 		status = hcd->driver->start_port_reset(hcd, port_num);
 
-	/* run khubd shortly after (first) root port reset finishes;
+	/* allocate hub_wq shortly after (first) root port reset finishes;
 	 * it may issue others, until at least 50 msecs have passed.
 	 */
 	if (status == 0)
@@ -2383,7 +2383,7 @@
 	if (hcd->rh_registered) {
 		clear_bit(HCD_FLAG_POLL_RH, &hcd->flags);
 
-		/* make khubd clean up old urbs and devices */
+		/* make hub_wq clean up old urbs and devices */
 		usb_set_device_state (hcd->self.root_hub,
 				USB_STATE_NOTATTACHED);
 		usb_kick_hub_wq(hcd->self.root_hub);
@@ -2393,7 +2393,7 @@
 		if (hcd->rh_registered) {
 			clear_bit(HCD_FLAG_POLL_RH, &hcd->flags);
 
-			/* make khubd clean up old urbs and devices */
+			/* make hub_wq clean up old urbs and devices */
 			usb_set_device_state(hcd->self.root_hub,
 					USB_STATE_NOTATTACHED);
 			usb_kick_hub_wq(hcd->self.root_hub);
@@ -2655,7 +2655,7 @@
 	set_bit(HCD_FLAG_HW_ACCESSIBLE, &hcd->flags);
 
 	/* HC is in reset state, but accessible.  Now do the one-time init,
-	 * bottom up so that hcds can customize the root hubs before khubd
+	 * bottom up so that hcds can customize the root hubs before hub_wq
 	 * starts talking to them.  (Note, bus id is assigned early too.)
 	 */
 	if ((retval = hcd_buffer_create(hcd)) != 0) {