doc: announce changes in IPsec SA config option struct

doc: announce changes in IPsec SA config option struct

Propose new fields to support offloads like
- IPsec inner checksum(L3/L4)
- IPsec tunnel header verification
- TSO
- etc
in the structure ``rte_security_ipsec_sa_options``.

Signed-off-by: Archana Muniganti <marchana@marvell.com>
Signed-off-by: Tejasree Kondoj <ktejasree@marvell.com>
Acked-by: Akhil Goyal <gakhil@marvell.com>
Acked-by: Radu Nicolau <radu.nicolau@intel.com>
Acked-by: Hemant Agrawal <hemant.agrawal@nxp.com>
Acked-by: Jerin Jacob <jerinj@marvell.com>