qlcnic: Fix NULL dereference in error path.

o Fix for smatch tool reported error
   drivers/net/ethernet/qlogic/qlcnic/qlcnic_main.c:2029
   qlcnic_probe() error: potential NULL dereference 'adapter'.
o While returning from an error path in probe, adapter is not
  initialized. So do not access adapter in cleanup path.

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