Accumulate the total number of sent packets per-link to find out how far
the encryption sequence number has progressed. Use this number as the
initial security sequence number after recovery.

This consolidates security sequence handling for both chip families, as
we no longer have to rely on 12xx specific Tx completion.

A fortunate side effect of this is correct management of seq numbers for
AP roles and multi-role scenarios.

When a link is removed we save the last seq number on a persistent part
of the wlvif. This helps the data survive through recoveries/suspends,
which also entail changes in the hlid of the link.

This functionality is STA only currently.
Signed-off-by: Arik Nemtsov <arik@wizery.com>
Signed-off-by: Luciano Coelho <coelho@ti.com>