net/mlx5e: Add NIC attributes for offloaded TC flows

Add structure that contains the attributes related to offloaded
NIC flows. Currently it has the actions and flow tag.

While here, do xmas tree cleanup of the TC configure function.

This patch doesn't change any functionality.

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