net/mlx5: fs, remove unused member

Counter is in struct fte, remove it.

Signed-off-by: Mark Bloch <mbloch@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Link: https://patch.msgid.link/20240911201757.1505453-7-saeed@kernel.org


Signed-off-by: Jakub Kicinski <kuba@kernel.org>