xfs: move xfs_types.h to libxfs

The types used by the core XFS code are common between kernel and
userspace. xfs_types.h is duplicated in both kernel and userspace,
so move it to libxfs along with all the other shared code.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dave Chinner <david@fromorbit.com>