ax8817x_unbind does not free the interrupt URB after unlinking.

Noticed that the net->status already has a flag for link so my
private structure variable for link was redundant.  Worked around
this and was able to kill off the unique ax8817x_get_link() function
in the process.
Signed-off-by: David Hollis <dhollis@davehollis.com>
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>