net/mlx5e: Move MACsec flow steering and statistics database from ethernet to core

Since now MACsec flow steering (macsec_fs) and MACsec statistics (stats)
are maintained by the core driver, move their data as well to be saved
inside core structures instead of staying part of ethernet MACsec database.

In addition cleanup all MACsec stats functions from the ethernet MACsec
code and move what's needed to be part of macsec_fs instead.

Signed-off-by: Patrisious Haddad <phaddad@nvidia.com>
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>