net: ethernet: ti: ale: clean ale tbl on init and intf restart

Clean CPSW ALE on init and intf restart (up/down) to avoid reading obsolete
or garbage entries from ALE table.

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