staging/hfi1: Add building blocks for TID caching

Functions added by this patch are building blocks for the upcoming
TID caching functionality. The functions added are currently unsed
(and marked as such.)

The functions' purposes are to find physically contigous pages in
the user's virtual buffer, program the RcvArray group entries with
these physical chunks, and unprogram the RcvArray groups.

Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Mitko Haralanov <mitko.haralanov@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>