xfs_logprint: Fix super block buffer interpretation issue

xfs_logprint: Fix super block buffer interpretation issue

When using xfs_logprint to interpret the buffer of the super block, the
icount will always be 6360863066640355328 (0x5846534200001000). This is
because the offset of icount is incorrect, causing xfs_logprint to
misinterpret the MAGIC number as icount.
This patch fixes the offset value of the SB counters in xfs_logprint.

Before this patch:
icount: 6360863066640355328  ifree: 5242880  fdblks: 0  frext: 0

After this patch:
icount: 10240  ifree: 4906  fdblks: 37  frext: 0

Suggested-by: Darrick J. Wong <djwong@kernel.org>
Suggested-by: Dave Chinner <david@fromorbit.com>
Signed-off-by: Chi Zhiling <chizhiling@kylinos.cn>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>