staging/rdma/hfi1: Implement LED beaconing for maintenance

This patch implements LED beaconing for maintenance. A MAD packet with
the LEDInfo attribute set to 1 will enable LED beaconing with a duty
cycle of 2s on and 1.5s off. A MAD packet with the LEDInfo attribute
set to 0 will disable beaconing and return the LED to normal operation.

Reviewed-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Easwar Hariharan <easwar.hariharan@intel.com>
Signed-off-by: Mitko Haralanov <mitko.haralanov@intel.com>
Signed-off-by: Jubin John <jubin.john@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>