xfs: minor cleanups of the quota functions

This series reworks some of the internal quota APIs and cleans up some
of the function calls so that we have a clean(er) place to start the
space reclamation patchset.  The first five patches clean up the
existing quota transaction helpers.  The next five patches create a
common helper to allocate space, quota, and transaction to handle a file
modification.  The final three patches of the series create common
helpers to do more or less the same thing for file creation and chown
operations.  The goal of these changes is to reduce open-coded idioms,
which makes the job of the space reclamation patchset easier since we
can now (mostly) hide the retry loops within single functions.

v2: rework the xfs_quota_reserve_blkres calling conventions per hch
v3: create new xfs_trans_alloc* helpers that will take care of free
    space and quota reservation all at once for block allocations, inode
    creation, and chown operations, to simplify the subsequent patches.
v4: fix some jump labels, improve commit messages, call out a quota
    accounting fix on dax files, fix some locking conventions with
    reflink
v5: refactor the chown transaction allocation into a helper function,
    fix a longstanding quota bug where incore delalloc reservations were
    lost if fssetxattr failed, other cleanups
v6: streamline the chown quota reservation code by moving it to
    xfs_trans_alloc_ichange.