net: macb: fix macb_get/set_wol() when moving to phylink

Keep previous function goals and integrate phylink actions to them.

phylink_ethtool_get_wol() is not enough to figure out if Ethernet driver
supports Wake-on-Lan.
Initialization of "supported" and "wolopts" members is done in phylink
function, no need to keep them in calling function.

phylink_ethtool_set_wol() return value is considered and determines
if the MAC has to handle WoL or not. The case where the PHY doesn't
implement WoL leads to the MAC configuring it to provide this feature.

Fixes: 7897b071

 ("net: macb: convert to phylink")
Cc: Claudiu Beznea <claudiu.beznea@microchip.com>
Cc: Harini Katakam <harini.katakam@xilinx.com>
Cc: Antoine Tenart <antoine.tenart@bootlin.com>
Cc: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Nicolas Ferre <nicolas.ferre@microchip.com>
Signed-off-by: David S. Miller <davem@davemloft.net>