ethernet: specify swol ioctl and set wol when non zero

Only set wol on an ethernet device if wol options have been initialized.
Otherwise, leave them alone.
ethernet: augment wol options formatting to take into account disabled flag
compat: fix string empty check and enable wol options dump to config
cleanup: remove some debugs used for development
ethernet: enable checks for supported wol options when reading and applying

Before setting wol options, grab existing wolinfo to determine if options
requested are even supported.
schema: add flags to wol schema to silence warning