xfs: updates for 4.10-rc1

Contained in this update:
- DAX PMD vaults via iomap infrastructure
- Direct-io support in iomap infrastructure
- removal of now-redundant XFS inode iolock, replaced with VFS i_rwsem
- synchronisation with fixes and changes in userspace libxfs code
- extent tree lookup helpers
- lots of little corruption detection improvements to verifiers
- optimised CRC calculations
- faster buffer cache lookups
- deprecation of barrier/nobarrier mount options - we always use
  REQ_FUA/REQ_FLUSH where appropriate for data integrity now
- cleanups to speculative preallocation
- miscellaneous minor bug fixes and cleanups
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1
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=HwDG
-----END PGP SIGNATURE-----