IB/hfi1: Do not set physical link state if DC is in the shutdown state

If the DC is in shutdown state, the set link state function will return
an error.  Since this is not a failure in this state, make sure to
only call set link state if the DC is on.

Reviewed-by: Easwar Hariharan <easwar.hariharan@intel.com>
Signed-off-by: Michael J. Ruhl <michael.j.ruhl@intel.com>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>