octeontx2-pf: Implement ingress/egress VLAN offload

This patch implements egress VLAN offload by appending NIX_SEND_EXT_S
header to NIX_SEND_HDR_S. The VLAN TCI information is specified
in the NIX_SEND_EXT_S. The VLAN offload in the ingress path is
implemented by configuring the NIX_RX_VTAG_ACTION_S to strip and
capture the outer vlan fields. The NIX PF allocates one MCAM entry
for Rx VLAN offload.

Signed-off-by: Hariprasad Kelam <hkelam@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>