USB: EHCI: store reason for unlinking a QH

This patch replaces the "exception" bitflag in the ehci_qh structure
with a more explicit "unlink_reason" bitmask.  This is for use in the
following patch, where we will need to have a good idea of the
reason for unlinking a QH, not just "something exceptional happened".

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Tested-by: Michael Reutman <mreutman@epiqsolutions.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/usb/host/ehci-timer.c b/drivers/usb/host/ehci-timer.c
index 424ac5d..37a3e0d 100644
--- a/drivers/usb/host/ehci-timer.c
+++ b/drivers/usb/host/ehci-timer.c
@@ -237,6 +237,7 @@
 				ehci->intr_unlink_wait_cycle))
 			break;
 		list_del_init(&qh->unlink_node);
+		qh->unlink_reason |= QH_UNLINK_QUEUE_EMPTY;
 		start_unlink_intr(ehci, qh);
 	}