octeontx2-af: Modify default KEX profile to extract TX packet fields

The current default Key Extraction(KEX) profile can only use RX
packet fields while generating the MCAM search key. The profile
can't be used for matching TX packet fields. This patch modifies
the default KEX profile to add support for extracting TX packet
fields into MCAM search key. Enabled Tx KPU packet parsing by
configuring TX PKIND in tx_parse_cfg.

Modified the KEX profile to extract 2 bytes of VLAN TCI from an
offset of 2 bytes from LB_PTR. The LB_PTR points to the byte offset
where the VLAN header starts. The NPC KPU parser profile has been
modified to point LB_PTR to the starting byte offset of VLAN header
which points to the tpid field.

Signed-off-by: Stanislaw Kardach <skardach@marvell.com>
Signed-off-by: Sunil Goutham <sgoutham@marvell.com>
Signed-off-by: Naveen Mamindlapalli <naveenm@marvell.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>