sky2: remove dual port workaround

This workaround was added to deal with NAPI core and how
it affected dual port shared polling. It turned out not to
be necessary. Stopping device 0 only doesn't stop NAPI from
working completely after that.

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