LU-16501 tgt: skip free inodes in OST weights

LU-16501 tgt: skip free inodes in OST weights

In lu_tgt_qos_weight_calc() calculate the target weight consistently
with how the per-OST and per-OSS penalty calculation is done in
ltd_qos_penalties_calc().  Otherwise, the QOS weighting calculations
combine two different units, which incorrectly weighs allocations on
OST with more free inodes over those with more free space.

Fixes: d3090bb2b486 ("LU-11213 lod: share object alloc QoS code with LMV")
Signed-off-by: Andreas Dilger <adilger@whamcloud.com>
Change-Id: I1ccc52d7ad5dc440ae48403ba129efd6a0a51c33