IB/hfi1: Create API for auto activate

Add an auto activate routine for use by the interrupt handler.

Link: https://lore.kernel.org/r/20200106134210.119356.43079.stgit@awfm-01.aw.intel.com


Reviewed-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Signed-off-by: Kaike Wan <kaike.wan@intel.com>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>