net/mlx5e: Fix MACsec state loss upon state update in offload path
The packet number attribute of the SA is incremented by the device rather
than the software stack when enabling hardware offload. Because the packet
number attribute is managed by the hardware, the software has no insight
into the value of the packet number attribute actually written by the
device.
Previously when MACsec offload was enabled, the hardware object for
handling the offload was destroyed when the SA was disabled. Re-enabling
the SA would lead to a new hardware object being instantiated. This new
hardware object would not have any recollection of the correct packet
number for the SA. Instead, destroy the flow steering rule when
deactivating the SA and recreate it upon reactivation, preserving the
original hardware object.