net/mlx5e: Move IPsec flow table creation to separate function

Even now, to support IPsec crypto, the RX and TX paths use same
logic to create flow tables. In the following patches, we will
add more tables to support IPsec packet offload. So reuse existing
code and rewrite it to support IPsec packet offload from the beginning.

Reviewed-by: Raed Salem <raeds@nvidia.com>
Reviewed-by: Saeed Mahameed <saeedm@nvidia.com>
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>