RDMA/mlx5: Don't keep umrable 'page_shift' in cache entries

mkc.log_page_size can be changed using UMR. Therefore, don't treat it as a
cache entry property.

Removing it from struct mlx5_cache_ent.

All cache mkeys will be created with default PAGE_SHIFT, and updated with
the needed page_shift using UMR when passing them to a user.

Link: https://lore.kernel.org/r/20230125222807.6921-2-michaelgur@nvidia.com
Signed-off-by: Aharon Landau <aharonl@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>