net/mlx5e: Use the full tunnel key info for encapsulation offload house-keeping

Currently we use subset of the input tunnel key fields (id, ip daddr,
dst port) which are provided by upper layers to indentify flows that should
go through the same encapsulation and maintain the HW encapsulation table.

This is redundant and can get us wrong.

Instead, keep a copy of the ip tunnel info provided by the user
through TC and have the tunnel key part as the key to our internal hash.

Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Reviewed-by: Hadar Hen Zion <hadarh@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>