xfs: move incore structures out of xfs_da_format.h

commit a39f089a25e75c3d17b955d8eb8bc781f23364f3 upstream.

Move the abstract in-memory version of various btree block headers
out of xfs_da_format.h as they aren't on-disk formats.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Acked-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Chandan Babu R <chandan.babu@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>