net/mlx5e: Delete unneeded function argument

priv argument is not used by the function, delete it.

Fixes: a8984281 ("net/mlx5e: Merge per priority stats groups")
Signed-off-by: Yuval Shaia <yuval.shaia@oracle.com>
Reviewed-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>