net: ethernet: ti: am65-cpsw: enable hw auto ageing

The AM65x ALE supports HW auto-ageing which can be enabled by programming
ageing interval in ALE_AGING_TIMER register. For this CPSW fck_clk
frequency has to be know by ALE.

This patch extends cpsw_ale_params with bus_freq field and enables ALE HW
auto ageing for AM65x CPSW2G ALE version.

Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: David S. Miller <davem@davemloft.net>