smb: delete an unnecessary statement

We don't need to set the list iterators to NULL before a
list_for_each_entry() loop because they are assigned inside the
macro.

Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Reviewed-by: Mukesh Ojha <quic_mojha@quicinc.com>
Signed-off-by: Steve French <stfrench@microsoft.com>