USB: xhci: Fix dropping endpoints from the xHC schedule.

When an endpoint is to be dropped from the hardware bandwidth schedule, we
want to clear its add flag.

Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/usb/host/xhci-hcd.c

@@ -895,7 +895,7 @@ int xhci_drop_endpoint(struct usb_hcd *hcd, struct usb_device *udev,
 	ctrl_ctx->drop_flags |= drop_flag;
 	new_drop_flags = ctrl_ctx->drop_flags;
 
-	ctrl_ctx->add_flags = ~drop_flag;
+	ctrl_ctx->add_flags &= ~drop_flag;
 	new_add_flags = ctrl_ctx->add_flags;
 
 	last_ctx = xhci_last_valid_endpoint(ctrl_ctx->add_flags);