octeontx2-af: Add LSO format configuration mailbox

NIX_AF_LSO_FORMAT(0..31)_FIELD(0..7) register enables an SW defined
means to define LSO packet modification formats.

0..31 works as an index to choose the algorithm, On success, the mailbox
returns the index to the client of chosen LSO algorithm selection.
This index will be used in configuring the transmit descriptors.

Add mailbox interface to dynamically reserve and configure LSO format.

This commit also fixes 'sizem1' for NIX_LSOALG_TCP_FLAGS
to '1' i.e 2 Bytes.

Signed-off-by: Nithin Dabilpuram <ndabilpuram@marvell.com>
Signed-off-by: Sunil Goutham <sgoutham@marvell.com>
Signed-off-by: Jerin Jacob <jerinj@marvell.com>
Signed-off-by: David S. Miller <davem@davemloft.net>