sky2: disable support for 88E8056

This device is having all sorts of problems that lead to data corruption
and system instability.  It gets receive status and data out of order,
it generates descriptor and TSO errors, etc.

Until the problems are resolved, it should not be used by anyone
who cares about there system.

Signed-off-by: Stephen Hemminger <shemminger@linux-foundation.org>
Signed-off-by: Jeff Garzik <jeff@garzik.org>