USB: EHCI: add separate IAA watchdog timer

This patch (as1028) was mostly written by David Brownell; I made only
a few changes (extra log info and a small bug fix -- which might
account for why David's version had to be reverted).  It adds a new
watchdog timer to the ehci-hcd driver to be used exclusively for
detecting lost or missing IAA notifications.

Previously a shared timer had been used, which may have led to some
problems as reported by Christian Hoffmann.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Cc: David Brownell <david-b@pacbell.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/usb/host/ehci-dbg.c

@@ -786,9 +786,7 @@ static ssize_t fill_registers_buffer(struct debug_buffer *buf)
 	}
 
 	if (ehci->reclaim) {
-		temp = scnprintf (next, size, "reclaim qh %p%s\n",
-				ehci->reclaim,
-				ehci->reclaim_ready ? " ready" : "");
+		temp = scnprintf(next, size, "reclaim qh %p\n", ehci->reclaim);
 		size -= temp;
 		next += temp;
 	}