net/mlx5e: Support MACsec offload extended packet number (EPN)

MACsec EPN splits the packet number (PN) into two 32-bits fields,
epn_lsb (32 least significant bits (LSBs) of PN) and epn_msb (32
most significant bits (MSBs) of PN).
Epn_msb bits are managed by SW and for that HW is required to send
an object change event of type EPN event notifying the SW to update
the epn_msb in addition, once epn_msb is updated SW update HW with
the new epn_msb value for HW to perform replay protection.
To prevent HW from stopping while handling the event, SW manages
another bit for HW called epn_overlap, HW uses the latter to get
an indication regarding how to read the epn_msb value correctly
while still receiving packets.
Add epn event handling that updates the epn_overlap and epn_msb for
every 2^31 packets according to the following logic:
if epn_lsb crosses 2^31 (half sequence number wraparound) upon HW
relevant event, SW updates the esn_overlap value to OLD (value = 1).
When the epn_lsb crosses 2^32 (full sequence number wraparound)
upon HW relevant event, SW updates the esn_overlap to NEW
(value = 0) and increment the esn_msb.
When using MACsec EPN a salt and short secure channel id (ssci)
needs to be provided by the user, when offloading EPN need to pass
this salt and ssci to the HW to be used in the initial vector (IV)
calculations.

Reviewed-by: Raed Salem <raeds@nvidia.com>
Signed-off-by: Emeel Hakim <ehakim@nvidia.com>
Reviewed-by: Tariq Toukan <tariqt@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>