drivers: net: phy: at803x: seperate wol specific code to wol standard apis

WOL is initilized in phy config_init, but there are standard apis
(set_wol/get_wol) for WOL in phy frame work. So this patch moves
WOL specific code from config_init to wol standard apis.

Cc: Matus Ujhelyi <ujhelyi.m@gmail.com>
Signed-off-by: Mugunthan V N <mugunthanvnm@ti.com>
Signed-off-by: David S. Miller <davem@davemloft.net>