jfs: truncate good inode pages when hard link is 0

The fileset value of the inode copy from the disk by the reproducer is
AGGR_RESERVED_I. When executing evict, its hard link number is 0, so its
inode pages are not truncated. This causes the bugon to be triggered when
executing clear_inode() because nrpages is greater than 0.

Reported-by:  <syzbot+6e516bb515d93230bc7b@syzkaller.appspotmail.com>
Closes: https://syzkaller.appspot.com/bug?extid=6e516bb515d93230bc7b


Signed-off-by: Lizhi Xu <lizhi.xu@windriver.com>
Signed-off-by: Dave Kleikamp <dave.kleikamp@oracle.com>