xfs: only log freed extents for the current RTG in zoned growfs

xfs: only log freed extents for the current RTG in zoned growfs

Otherwise a power fail or crash during growfs could lead to an
elevated sb_rblocks counter.

Note that the step function is much simpler compared to the classic RT
allocator as zoned RT sections must be aligned to real time group
boundaries.

Fixes: 01b71e64bb87 ("xfs: support growfs on zoned file systems")
Cc: <stable@vger.kernel.org> # v6.15
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Signed-off-by: Carlos Maiolino <cem@kernel.org>