octeontx2-af: Code restructure to handle TC outer VLAN offload

Moved the TC outer VLAN offload support to a separate function.
This change is done to handle all VLAN related changes cleanly from
a dedicated function.

Signed-off-by: Suman Ghosh <sumang@marvell.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://lore.kernel.org/r/20230804045935.3010554-2-sumang@marvell.com


Signed-off-by: Jakub Kicinski <kuba@kernel.org>