IB/hfi1: Use host_link_state to read state when DC is shut down

When DC is shut down (by e.g.  disconnecting the cable), the
driver should use host_link_state to get port's current
physical state. This is due to the fact that physical state
is read from DC's CSRs and when DC is shut down and state is
changed, its registers are not impacted.

Reviewed-by: Jakub Byczkowski <jakub.byczkowski@intel.com>
Signed-off-by: Bartlomiej Dudek <bartlomiej.dudek@intel.com>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>