Revert "net/mlx5: Add MPCNT register infrastructure"

This reverts commit 7f503169.

Fixes: 7f503169 ("net/mlx5: Add MPCNT register infrastructure")
Signed-off-by: Gal Pressman <galp@mellanox.com>
Reported-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>