net/mlx5e: Enhance flow counter scheme for offloaded TC eswitch rules

Assign a counter dev attribute according to device capability and use
it for management of counters related to offloaded eswitch TC flows.

With upcoming support for uplink LAG, we have two HW rules per one
logical SW (TC) rule. Although the HW supports attaching one counter
to multiple rules, we are allocating counter per HW rule.

We need this separation for two reasons:

1. "flow eswitch" counter affinity HW require the counter to be
allocated on the device where the eswitch rule is set.

2. for some use-cases (multi-path routing) each HW flow relates to
different neighbour, hence our neigh update logic must have a per-rule
HW accountant in order to provide the proper feedback to the kernel.

Signed-off-by: Shahar Klein <shahark@mellanox.com>
Signed-off-by: Roi Dayan <roid@mellanox.com>
Reviewed-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>