xfs: get rid of xfs_growfs_{data,log}_t

Such usage isn't encouraged by the kernel coding style. Leave the
definitions alone in case of userspace users.

Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Gao Xiang <hsiangkao@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>