qlcnic: Fix link speed display for 82xx adapter

o Do not obtain link speed from register when adapter
  link is down.

Signed-off-by: Rajesh Borundia <rajesh.borundia@qlogic.com>
Signed-off-by: Shahed Shaikh <shahed.shaikh@qlogic.com>
Signed-off-by: David S. Miller <davem@davemloft.net>