LINK_INBAND_ENABLE isn't valid for 5GBase-R/10GBase-R modes which
by definition don't support any in-band an. Correctly report
LINK_INBAND_DISABLE to fix 10G fiber SFP modules no longer working.
While at it also get rid of downstream pn-swap properties in favor
of using the upstream schema.
Signed-off-by: Daniel Golle <daniel@makrotopia.org>