xfs: refactor buffer cancellation table allocation

xfs: refactor buffer cancellation table allocation

Source kernel commit: 2723234923b3294dbcf6019c288c87465e927ed4

Move the code that allocates and frees the buffer cancellation tables
used by log recovery into the file that actually uses the tables.  This
is a precursor to some cleanups and a memory leak fix.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
Signed-off-by: Eric Sandeen <sandeen@sandeen.net>