net/mlx5e: Remove unused define MLX5_MPWRQ_STRIDES_PER_PAGE

Clean it up as it's not in use.

Fixes: d9d9f156

 ("net/mlx5e: Expand WQE stride when CQE compression is enabled")
Signed-off-by: Tariq Toukan <tariqt@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>