staging/rdma/hfi1: HFI reports wrong offline disabled reason when cable removed

Removing QSFP cable should report 'No Local Media' instead of
'Transient' as reported by 'opaportinfo'.
Workaround is to change the state to
OPA_LINKDOWN_REASON_LOCAL_MEDIA_NOT_INSTALLED in cable handler.

With cable still removed, 'opaportinfo bounce' should not cause a
state change to Polling, as reported by 'opaportinfo'.
Resolution is to prevent physical state change from Offline->Polling.

Use a macro to mask lower nibble of OPA_LINKDOWN_REASON* as needed
for offline_disabled_reason.

Reviewed-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Reviewed-by: Easwar Hariharan <easwar.hariharan@intel.com>
Reviewed-by: Dean Luick <dean.luick@intel.com>
Reported-by: Todd Rimmer <todd.rimmer@intel.com>
Signed-off-by: Bryan Morgan <bryan.c.morgan@intel.com>
Signed-off-by: Jubin John <jubin.john@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>