osd: EC Optimizations: Update pwlc in pg_info_t

osd: EC Optimizations: Update pwlc in pg_info_t

Optimized EC pools add extra data to the log entry to track
which shards were updated by a partial write. When the log
entry is completed this needs to be summarized in the
partial_writes_last_complete map in pg_info_t.

Summarising this data in pg_info_t makes it easy to determine
whether the reason a shard is behind is because it is missing
update or has just not been involved in recent updates. This
also ensures that even if there is a long sequence of
updates that all skip updating a shard that a record of this
is retained in the info structure even after the log
has been trimmed.

Edited by aainscow as suggested in comment here:
https://github.com/ceph/ceph/pull/62522/files#r2050803678

Signed-off-by: Bill Scales <bill_scales@uk.ibm.com>
Signed-off-by: Alex Ainscow <aainscow@uk.ibm.com>