IB/hfi1: Improve LED beaconing

The current LED beaconing code is unclear and uses the timer handler to
turn off the timer. This patch simplifies the code by removing the
special semantics of timeon = timeoff = 0 being interpreted as a request
to turn off the beaconing.

Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Reviewed-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Easwar Hariharan <easwar.hariharan@intel.com>
Signed-off-by: Jubin John <jubin.john@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>