xfs: detach dquots from inode if we don't need to inactivate it

If we don't need to inactivate an inode, we can detach the dquots and
move on to reclamation.  This isn't strictly required here; it's a
preparation patch for deferred inactivation per reviewer request[1] to
move the creation of xfs_inode_needs_inactivation into a separate
change.  Eventually this !need_inactive chunk will turn into the code
path for inodes that skip xfs_inactive and go straight to memory
reclaim.

[1] https://lore.kernel.org/linux-xfs/20210609012838.GW2945738@locust/T/#mca6d958521cb88bbc1bfe1a30767203328d410b5


Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>