net: ethernet: ti: am65-cpsw: Fix hardware switch mode on suspend/resume

On low power during system suspend the ALE table context is lost.
Save the ALE context before suspend and restore it after resume.

Signed-off-by: Roger Quadros <rogerq@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>