net/mlx5: E-Switch, move work queue generation counter

net/mlx5: E-Switch, move work queue generation counter

The generation counter in mlx5_esw_functions is used to detect stale
work items on the E-Switch work queue. Move it from mlx5_esw_functions
to the top-level mlx5_eswitch struct so it can guard all work types,
not just function-change events.

This is a mechanical refactor: no behavioral change.

Signed-off-by: Mark Bloch <mbloch@nvidia.com>
Reviewed-by: Cosmin Ratiu <cratiu@nvidia.com>
Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
Link: https://patch.msgid.link/20260428051018.219093-2-tariqt@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>