Staging: unisys: use after free in list_for_each()

These should be using the _safe version of list_for_each() because we
free the current element and it leads to a use after free bug.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>