This code was added before we had protection data length
calculation (in iser_send_command), so we needed to calc
the sg data length from the sg itself. This is not needed
anymore.

This patch does not change any functionality.
Signed-off-by: NSagi Grimberg <sagig@mellanox.com>
Signed-off-by: NAdir Lev <adirl@mellanox.com>
Signed-off-by: NDoug Ledford <dledford@redhat.com>