IB/{hfi1,qib}: Cleanup open coded sge sizing

Sge sizing is done in several places using an open coded method.

This can cause maintenance issues.  The open coded method is
encapsulated in a helper routine.  The helper was introduced with
commit:

1198fcea

 ("IB/hfi1, rdmavt: Move SGE state helper routines into
rdmavt")

Update all call sites that have the open coded path with the helper
routine.

Reviewed-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Signed-off-by: Michael J. Ruhl <michael.j.ruhl@intel.com>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>