net: usb: ax88179_178a: wol optimizations

- Check if wol is supported on reset instead of everytime get_wol
is called.
- Save wolopts in private data instead of relying on the HW to save it.
- Defer enabling WoL until suspend instead of enabling it everytime
set_wol is called.

Signed-off-by: Justin Chen <justinpopo6@gmail.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>